Methods, processes, and apparatuses for producing welded substrates

ABSTRACT

A welding process may be configured to convert a substrate into a welded substrate by applying a process solvent to the substrate, wherein the process solvent interrupts one or more intermolecular force between one or more component in the substrate. The substrate may be configured as a natural fiber, such as cellulose, hemicelluloses, and silk. The process solvent may be configured as an ionic-liquid based solvent and the welded substrate may be a congealed network after the process solvent has been adequately swollen and/or mobilized the substrate. A welding process may be configured such that individual fibers of a substrate are not fully dissolved such that material in the fiber core may be left in the native state by controlling process variables. The welding process fibers may have a tenacity 10% or 20% greater or a diameter 25% less than that of a cellulosic-based yarn substrate.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in part of and claims priorityfrom pending U.S. patent application Ser. No. 14/876,351 filed on Oct.6, 2015 which claimed the benefit of U.S. provisional App. Nos.62/060,524 filed on Oct. 6, 2014 and 62/061,665 filed on Oct. 8, 2014,all of which are incorporated by reference herein in their entireties.Applicant also claims priority to U.S. provisional App. Nos. 62/313,291filed on Mar. 25, 2016, 62/365,752 filed on Jul. 22, 2016 and 62/446,646filed on Jan. 16, 2017, all of which are incorporated by referenceherein in their entireties.

FIELD OF THE INVENTION

The present disclosure related to methods for producing fiber compositesand products that may be made from those fiber composites.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

No federal funds were used to develop or create the invention disclosedand described in the patent application.

BACKGROUND

Synthetic polymers such as polystyrene are routinely welded usingsolvents such as dichloromethane. Ionic liquids (e.g.,1-ethyl-3-methylimidazolium acetate) can dissolve natural fiberbiopolymers (e.g., cellulose and silk) without derivatization. Naturalfiber welding is a process by which biopolymer fibers are fused in amanner roughly analogous to traditional plastic welding.

As disclosed in U.S. Pat. No. 8,202,379, which is incorporated byreference herein in its entirety, one type of process solvent that maybe used for partially dissolving a natural fiber for structural andchemical modifications is ionic liquid-based solvents. This patentdiscloses basic principles developed using bench top equipment andmaterials. However, among various other things, this patent fails todisclose processes and apparatuses for making composite materials at acommercial scale.

There are examples of natural fibers biopolymer solutions that are castinto molds to create a desired generally two-dimensional shape. In thesecases, the biopolymer is fully dissolved so that the original structureis disrupted and biopolymers are denatured. By contrast, with fiberwelding, the fiber interior (the core of each individual fiber) isintentionally left in its native state. This is advantageous because thefinal structure composed of biopolymers retains some of the originalmaterial properties for creating robust materials from biopolymers suchas silk, cellulose, chitin, chitosan, other polysaccharides andcombinations thereof.

Traditional methods of using biopolymer solutions are also disadvantagedin that there is a physical limit to how much polymer can be dissolvedin solution. For example, solutions that are 10% by mass cotton(cellulose) with 90% by mass ionic liquid solvent are viscous anddifficult to handle, even at elevated temperatures. The fiber weldingprocess allows fiber bundles to be manipulated into the desired shapebefore welding commences. The use and handling of natural fibers oftengrants control over the engineering of the final product that is notpossible for solution-based technologies.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments and together with thedescription, serve to explain the principles of the methods and systems.

FIG. 1 provides a schematic view of various aspects of a process forproducing welded substrates.

FIG. 2 provides a schematic view of various aspects of another processfor producing welded substrates.

FIG. 2A provides a schematic view of one type of process solventrecovery zone that may be used with a welding process.

FIG. 3 illustrates a process for addition and physical entrapment ofsolid materials within a fiber-matrix composite with the sub-processesor components of FIG. 3 called-out as FIGS. 3A-3E. Functional materialsare predispersed in the fiber matrix before welding.

FIG. 4 illustrates a process for addition and physical entrapment ofsolid materials within a fiber-matrix composite with the sub-processesor components of FIG. 4 called-out as FIGS. 4A-4D utilizing materials(pre)dispersed in an IL-based solvent.

FIG. 5 illustrates a process for addition and physical entrapment ofsolid materials within a fiber-matrix composite with the sub-processesor components of FIG. 5 called-out as FIGS. 5A-5D utilizing materials(pre)dispersed in an IL-based solvent with additional solubilizedpolymer.

FIG. 6A provides a side, cutaway view of one configuration of a processsolvent application zone.

FIG. 6B provides a perspective view of another configuration of aprocess solvent application zone.

FIG. 6C provides a perspective view of another configuration of aprocess solvent application zone.

FIG. 6D provides a side view of an apparatus that may be used withvarious welding processes.

FIG. 6E provides a side view of the apparatus from FIG. 6D, wherein theplates are differently positioned with respect to one another.

FIG. 6F provides a side view of an apparatus that may be used withvarious welding processes, wherein the apparatus may be configured foruse with a plurality of 1D substrates positioned adjacent one another.

FIG. 7A is a schematic view of a welding process that may be used toproduce the welded substrate shown in FIG. 7C.

FIG. 7B provides a scanning-electron microscope image of raw, 1Dsubstrate comprised of 30/1 ring-spun cotton yarn.

FIG. 7C provides a scanning-electron microscope image of the rawsubstrate shown in FIG. 7B after it has been processed in anotherwelding process with a process solvent comprised of an ionic liquid toproduce a welded substrate.

FIG. 7D provides a graphical representation of the stress (in grams)versus percent-elongation applied to both a representative raw yarnsubstrate sample and a representative welded yarn substrate sample fromFIG. 7C, wherein the top curve is the welded yarn substrate and thebottom trace is the raw.

FIG. 8A is a schematic view of a welding process that may be used toproduce the welded substrate shown in FIG. 8C.

FIG. 8B provides a scanning-electron microscope image of raw, 1Dsubstrate comprised of 30/1 ring-spun cotton yarn.

FIG. 8C provides a scanning-electron microscope image of the rawsubstrate shown in FIG. 8B after it has been processed in anotherwelding process with a process solvent comprised of an ionic liquid toproduce a welded substrate.

FIG. 8D provides a graphical representation of the stress (in grams)versus percent-elongation applied to both a representative raw yarnsubstrate sample and a representative welded yarn substrate sample fromFIG. 8C, wherein the top curve is the welded yarn substrate and thebottom trace is the raw.

FIG. 9A is a perspective view of a welding process that may beconfigured to produce the welded substrate shown in FIGS. 9C-9E.

FIG. 9B provides a scanning-electron microscope image of raw, 1Dsubstrate comprised of 30/1 ring-spun cotton yarn.

FIG. 9C provides a scanning-electron microscope image of the rawsubstrate shown in FIG. 9B after it has been processed in a weldingprocess with a process solvent comprised of an ionic liquid, wherein thewelded substrate is lightly welded.

FIG. 9D provides a scanning-electron microscope image of the rawsubstrate shown in FIG. 9B after it has been processed in a weldingprocess with a process solvent comprised of an ionic liquid, wherein thewelded substrate is moderately welded.

FIG. 9E provides a scanning-electron microscope image of the rawsubstrate shown in FIG. 9B after it has been processed in a weldingprocess with a process solvent comprised of an ionic liquid, wherein thewelded substrate is highly welded.

FIG. 9F provides an image of a fabric made from the welded substrateshown in FIG. 9D.

FIG. 9G provides a graphical representation of the stress (in grams)versus percent-elongation applied to both a representative raw yarnsubstrate sample and a representative welded yarn substrate sample fromFIGS. 9C and 9K, wherein the top curve is the welded yarn substrate andthe bottom trace is the raw.

FIG. 9H provides an image of a fabric made from the raw substrate shownin FIG. 9B on the left side of the picture and a fabric made from thewelded substrate shown in FIG. 9D on the right side of the picture.

FIGS. 9I & 9J provide images of a welded substrate that may beconsidered a shell welded substrate.

FIG. 9K provides a scanning-electron microscope image of the rawsubstrate shown in FIG. 9B after it has been processed in a weldingprocess with a process solvent comprised of an ionic liquid, wherein thewelded substrate is lightly welded.

FIG. 9L provides a scanning-electron microscope image of the rawsubstrate shown in FIG. 9B after it has been processed in a weldingprocess with a process solvent comprised of an ionic liquid, wherein thewelded substrate is moderately welded.

FIG. 9M provides a scanning-electron microscope image of the rawsubstrate shown in FIG. 9B after it has been processed in a weldingprocess with a process solvent comprised of an ionic liquid, wherein thewelded substrate is highly welded.

FIG. 10A is a perspective view of a welding process that may beconfigured to produce the welded substrate shown in FIGS. 10C-10F.

FIG. 10B provides a scanning-electron microscope image of multiple raw,1D substrates comprised of 30/1 ring-spun cotton yarn.

FIG. 10C provides a scanning-electron microscope image of the rawsubstrate shown in FIG. 10B after it has been processed in a weldingprocess with a process solvent comprised of a hydroxide, wherein thewelded substrate is lightly welded.

FIG. 10D provides a scanning-electron microscope image of the rawsubstrate shown in FIG. 10B after it has been processed in a weldingprocess with a process solvent comprised of a hydroxide, wherein thewelded substrate is moderately welded.

FIG. 10E provides a scanning-electron microscope image of the rawsubstrate shown in FIG. 10B after it has been processed in a weldingprocess with a process solvent comprised of a hydroxide, wherein thewelded substrate is highly welded.

FIG. 10F provides a magnified image of a portion of the center weldedsubstrate from FIG. 10E. FIG. 10G provides a graphical representation ofthe stress (in grams) versus percent-elongation applied to both arepresentative raw yarn substrate sample and a representative weldedyarn substrate sample from FIG. 10C, wherein the top curve is the weldedyarn substrate and the bottom trace is the raw.

FIG. 11A provides a schematic representation showing various aspects ofa modulated fiber welding process.

FIG. 11B provides a schematic representation showing other aspects of amodulated fiber welding process.

FIG. 11C provides a schematic representation showing other aspects of amodulated fiber welding process.

FIG. 11D provides a schematic representation showing other aspects of amodulated fiber welding process.

FIG. 11E provides an image of a welded substrate that has been producedvia a modulated welding process, wherein the portion on the right sideof the figure is lightly welded and the portion on the right side of thefigure is highly welded.

FIG. 11F provides another image of a fabric made from a modulated weldedsubstrate, wherein the fabric exhibits a heathering effect.

FIG. 12A provides scanning-electron microscope image of a raw, 2Dsubstrate comprised of denim.

FIG. 12B provides a scanning-electron microscope image of raw substratefrom FIG. 12A after it has been processed into a welded substrate thatis highly welded.

FIG. 12C provides scanning-electron microscope image of a raw, 2Dsubstrate comprised of a knitted fabric.

FIG. 12D provides a scanning-electron microscope image of raw substratefrom FIG. 12C after it has been processed into a welded substrate thatis moderately welded.

FIG. 12E provides a scanning-electron microscope image of a raw, 2Dsubstrate comprised of a jersey knit cotton fabric.

FIG. 12F provides a scanning-electron microscope image of raw substratefrom FIG. 12E after it has been processed into a welded substrate thatis lightly welded.

FIG. 12G provides a magnified scanning-electron microscope image of araw, 2D substrate comprised of a jersey knit cotton fabric.

FIG. 12H provides a magnified scanning-electron microscope image of rawsubstrate from FIG. 12E after it has been processed into a weldedsubstrate that is lightly welded.

FIG. 13 provides a scanning-electron microscope image of a welded yarnsubstrate produced with a welding process having a reconstitutionsolvent at approximately 20° C.

FIG. 14A provides a scanning-electron microscope image of a welded yarnsubstrate produced with a welding process having a reconstitutionsolvent at approximately 22° C.

FIG. 14B provides a scanning-electron microscope image of a differentwelded yarn substrate produced with a welding process having areconstitution solvent at approximately 40° C.

FIG. 15A provides x-ray diffraction data for a raw cotton yarn on plot Aand a cotton yarn reconstituted from a raw cotton yarn substrate thatwas fully dissolved in ionic liquid.

FIG. 15B provides x-ray diffraction data for three different welded yarnsubstrates produced from the same raw cotton yarn substrate shown inplot A of FIG. 15A

DETAILED DESCRIPTION Element Number Element Description (FIGS. 1 & 2)Substrate feed zone 1 Process solvent application zone 2 Processtemperature/pressure zone 3 Process solvent recovery zone 4 Drying zone5 Welded substrate collection zone 6 Solvent collection zone 7 Solventrecycling 8 Mixed gas collection 9 Mixed gas recycling 10 ElementDescription (FIGS. 3A-xx) Natural fiber substrate 10 Swollen naturalfiber substrate  11, 112 Welded substrate 12 Functional material 20Bonded functional material 21 Entrapped functional material 22 IL-basedprocess solvent 30 Process solvent/functional material mixture 32 Weldedfiber 40, 42 Polymer 53 Injector 60 Substrate input 61 Process solventinput 62 Application interface 63 Substrate outlet 64 Tray 70 Substrategroove 72 First plate 82 Second plate 84

Before the present methods and apparatuses are disclosed and described,it is to be understood that the methods and apparatuses are not limitedto specific methods, specific components, or to particularimplementations. It is also to be understood that the terminology usedherein is for the purpose of describing particular embodiments/aspectsonly and is not intended to be limiting.

As used in the specification and the appended claims, the singular forms“a,” “an,” and “the” include plural referents unless the context clearlydictates otherwise. Ranges may be expressed herein as from “about” oneparticular value, and/or to “about” another particular value. When sucha range is expressed, another embodiment includes from the oneparticular value and/or to the other particular value. Similarly, whenvalues are expressed as approximations, by use of the antecedent“about,” it will be understood that the particular value forms anotherembodiment. It will be further understood that the endpoints of each ofthe ranges are significant both in relation to the other endpoint, andindependently of the other endpoint.

“Optional” or “optionally” means that the subsequently described eventor circumstance may or may not occur, and that the description includesinstances where said event or circumstance occurs and instances where itdoes not.

“Aspect” when referring to a method, apparatus, and/or component thereofdoes not mean that limitation, functionality, component etc. referred toas an aspect is required, but rather that it is one part of a particularillustrative disclosure and not limiting to the scope of the method,apparatus, and/or component thereof unless so indicated in the followingclaims.

Throughout the description and claims of this specification, the word“comprise” and variations of the word, such as “comprising” and“comprises,” means “including but not limited to,” and is not intendedto exclude, for example, other components, integers or steps.“Exemplary” means “an example of” and is not intended to convey anindication of a preferred or ideal embodiment. “Such as” is not used ina restrictive sense, but for explanatory purposes.

Disclosed are components that can be used to perform the disclosedmethods and apparatuses. These and other components are disclosedherein, and it is understood that when combinations, subsets,interactions, groups, etc. of these components are disclosed that whilespecific reference of each various individual and collectivecombinations and permutation of these may not be explicitly disclosed,each is specifically contemplated and described herein, for all methodsand apparatuses. This applies to all aspects of this applicationincluding, but not limited to, steps in disclosed methods. Thus, ifthere are a variety of additional steps that can be performed it isunderstood that each of these additional steps can be performed with anyspecific embodiment or combination of embodiments of the disclosedmethods.

The present methods and apparatuses may be understood more readily byreference to the following detailed description of preferred aspects andthe examples included therein and to the Figures and their previous andfollowing description. Corresponding terms may be used interchangeablywhen referring to generalities of configuration and/or correspondingcomponents, aspects, features, functionality, methods and/or materialsof construction, etc. those terms.

It is to be understood that the disclosure is not limited in itsapplication to the details of construction and the arrangements ofcomponents set forth in the following description or illustrated in thedrawings. The present disclosure is capable of other embodiments and ofbeing practiced or of being carried out in various ways. Also, it is tobe understood that phraseology and terminology used herein withreference to device or element orientation (such as, for example, termslike “front”, “back”, “up”, “down”, “top”, “bottom”, and the like) areonly used to simplify description, and do not alone indicate or implythat the device or element referred to must have a particularorientation. In addition, terms such as “first”, “second”, and “third”are used herein and in the appended claims for purposes of descriptionand are not intended to indicate or imply relative importance orsignificance.

1. Definitions

Throughout this disclosure, various terms may be used to describecertain components of process, apparatuses, and/or other components thatmay be used in conjunction with the present disclosure. For clarity,definitions of some of those terms are provided immediately below.However, when used to describe such components, these terms and thedefinitions thereof are not meant to be limiting in scope unless soindicated in the following claims, but instead are meant to beillustrative of one or more aspects of the present disclosure.Additionally, the inclusion of any term and/or definition thereof is notmeant to require a manifestation of that component in any specificprocess or apparatus disclosed herein unless so indicated in thefollowing claims.

A. Substrate Materials

“Substrate” as used herein may include either a pure biomaterial (e.g.,cotton yarn, etc.), a plurality of biomaterials (e.g., lignocellulosicfibers mixed with silk fibers), or a material containing a known amountof a biomaterial. In one aspect, a substrate may contain naturalmaterials that contain at least one biopolymer component that is heldtogether by hydrogen bonding (e.g., cellulose). In certain aspects, theterm “substrate” may refer to synthetic materials, such as polyester,nylon, etc.; however, instances in which the term “substrate” refers tosynthetic materials typically will be specifically noted throughout. Thefusion or welding process may be performed in a way that limits thedenaturation of at least one component of the substrate. For example, alimited amount of a process solvent may be added at moderatetemperatures and pressures and for a controlled time to limit thedenaturation of lignocellulosic fibers.

“Cellulosic-based substrate” may include cotton, pulp, and/or otherrefined cellulosic fiber and/or particles, etc.

“Lignocellulosic-based substrate” may include wood, hemp, corn stover,bean straw, grass, etc. “Other sugar-based biopolymer substrates” mayinclude chitin, chitosan, etc.

“Protein-based substrates” may include keratin (e.g., wool, hooves,horns, nails), silk, collagen, elastin, tissues, etc.

“Raw substrate” as used herein may include any substrate that has a notbeen subjected to any welding process.

B. Substrate Format Types

Substrate formats can be a variety of commercially available orcustomized products. ‘Loose,’ one-dimensional (1D), two-dimensional(2D), and/or three-dimensional (3D) substrates are all possible for usein various processes according to the present disclosure. Finishedwelded substrates or composites may be shaped in 1D, 2D, and/or 3D,respectively. The following definitions are applicable to bothsubstrates and welded substrates (as defined further below).

“Loose” may include any natural fiber and/or particles or mixture ofnatural fibers and/or particles that is fed into the welding process ina loose, and/or relatively untangled format (e.g., mixtures of loosecotton with wood fibers and/or particles).

“1D” may include yarn and thread, both non-piled singled and piled yarnsand threads.

“2D” may include paper substitute (e.g., cardboard alternatives,packaging paper, etc.), board substitute (e.g., alternatives tohardboard, plywood, OSB, MDF, dimensional lumber, etc.).

“3D” may include automotive parts, structural building components (e.g.,extruded beams, joists, walls, etc.), furniture parts, toys, electronicscases and/or components, etc.

Generally, a resulting welded substrate or composite material may becomposed of significant amounts of natural material (e.g., materialproduced by lifeforms and/or enzymes), wherein the natural material maybe held together by the fusion or welding of the biopolymers of thenatural materials rather than glues, resins, and/or other adhesives.

C. Process Solvent System

“Process solvent” may include a material capable of disruptingintermolecular forces of the substrate (e.g., hydrogen bonds), andincludes materials that can swell, mobilize, and/or dissolve at leastone biopolymer component within the substrate and/or otherwise disruptthe forces that may bind one biopolymer component to another.

“Pure process solvents” may include a process solvent without additionaladditives, and may include ionic liquids, 3-ehtyl-1-methylimidizoliumacetate, 3-butyl-1-methylimidizolium chloride, and other similar saltscurrently known or later developed that serve to disrupt intermolecularforces of a substrate.

“Deep eutectic process solvents” may include ionic solvents thatincorporate one or more compound in a mixture form to give a eutecticwith a melting point lower than one or more of the components that makeup the mixture, and may further include a pure ionic liquid processsolvent mixed with other ionic liquids and/or molecular species.

“Mixed organic process solvents” may include ionic liquids (e.g.,3-ethyl-1-methylimidizolium acetate) mixed with polar protic (e.g.,methanol) and/or polar aprotic solvents (e.g., acetonitrile) as well assolutions containing 4-methylmorpholine 4-oxide (also known asN-methylmorpholine N-oxide, NMMO).

“Mixed inorganic process solvents” may include aqueous salt solutions(e.g., aqueous solutions of LiOH and/or NAOH that may be mixed with ureaor other molecular additives, aqueous guanidinium chloride, LiCl in N,N-dimethylacetamide (DMAc), etc.).

In an aspect, process solvents may contain additional functionalmaterials such as a relatively small amount (e.g., less than 10% bymass) fully solubilized natural polymer(s) (e.g., cellulose), but mayalso contain selected synthetic polymers (e.g. meta□aramid), as well asother functional materials.

D. Functional Material

“Functional material” may include natural or synthetic inorganicmaterials (e.g., magnetic or conductive materials, magneticmicroparticles, catalysts, etc.), natural or synthetic organic materials(e.g., carbon, dyes (including but not limited to florescent andphosphorescent), enzymes, catalysts, polymer, etc.), and/or devices(e.g., RFID tags, MEMS devices, integrated circuits) that may addfeatures, functionality, and/or benefits to a substrate. Additionally,functional materials may be placed in substrates and/or processsolvents.

E. Process Wetted Substrate

“Process wetted substrate” may refer to a substrate of any combinationof format and type that is wetted with a process solvent applied to allor a part of the substrate. Accordingly, a process wetted substrate maycontain some partially dissolved, mobilized natural polymer.

F. Reconstitution Solvent System

“Reconstitution solvent” may include a liquid that has a non□zero vaporpressure and may be capable of forming mixtures with ions from theprocess solvent system. In an aspect, one characteristic of areconstitution solvent system may be that it is not be capable ofdissolving natural materials substrates on its own. Generally, thereconstitution solvent may be used to separate and remove processsolvent ions from substrates. That is to say, in one aspectreconstitution solvent removes process solvent from a process wettedsubstrate. In so doing, the process wetted substrate may be transformedto a reconstituted wetted substrate as defined below.

Reconstitution solvents may include polar protic solvents (e.g., water,alcohols, etc.) and/or polar aprotic solvents (e.g., acetone,acetonitrile, ethyl acetate, etc.). Reconstitution solvents may bemixtures of molecular components and may include ionic components. In anaspect, a reconstitution solvent may be used to help control thedistribution of functional materials within a substrate. Areconstitution solvent may be configured to be chemically similar to orsubstantially chemically identical to a molecular additive in a processsolvent system.

In an aspect, a (pure) reconstitution solvent may be mixed with ioniccomponents to form a process solvent. A reconstitution solvent may beconfigured to be chemically similar to or substantially chemicallyidentical to a molecular additive in a process solvent system. Forexample, acetonitrile is a polar aprotic molecular liquid with anon-zero vapor pressure that is not capable of dissolving cellulose whenpure. Acetonitrile may be mixed with a sufficient amount of3-ethyl-1-methylimidizolium acetate to form a solution that is capableof disrupting hydrogen bonding, and acetonitrile may be used as thereconstitution solvent. Mixtures that contain the sufficientconcentration (ionic strength) of the appropriate ions are thus able toserve as a process solvent. Within the present disclosure, any mixturesof 3-ethyl-1-methylimidizolium acetate in acetonitrile that do notcontain sufficient ionic strength to dissolve or mobilize polymer of anatural substrate are considered to be a reconstitution solvent.

G. Reconstituted Wetted Substrate

“Reconstituted wetted substrate” may refer a process wetted substrate ofany combination of format and type that is wetted with thereconstitution solvent applied to all or part of the process wettedsubstrate. Generally, a reconstitution wetted substrate does not containpartially dissolved, mobilized natural polymer, which may be due to theremoval of the process solvent via the application of the reconstitutionsolvent.

H. Drying Gas Systems

“Drying gas” may include a material that is a gas at room temperatureand atmospheric pressure, but may be a supercritical fluid. In anaspect, the drying gas may be capable of mixing with and carrying thenon-zero vapor pressure components (e.g., all or a portion of thereconstitution solvent) from both a process wetted substrate and/or areconstituted wetted substrate. Drying gas may be pure gases (e.g.,nitrogen, argon, etc.) or mixtures of gases (e.g., air).

I. Welded Substrate

“Welded substrate” may be used to refer to a finished compositecomprised of at least one natural substrate in which one or moreindividual fibers and/or particles have been fused or welded togethervia a process solvent acting upon biopolymers from either those fibersand/or particles and/or action upon another natural material within thesubstrate. Generally, welded substrates may include “finishedcomposites” and/or “fiber-matrix composites.” Specifically,“fiber-matrix composite” may be used to refer to a welded substratehaving a natural substrate acting as both the fiber and the matrix ofthe welded substrate.

J. Welding

“Welding” as used herein may refer to joining and/or fusion of materialsby intimate intermolecular association of polymer.

2. General Welding Processes

The present disclosure provides various processes and/or apparatuses forconverting biopolymer containing fibrous and/or particulate substrateinto welded substrates (one example of which is a composite material),and also discloses various products that may be manufactured from thewelded substrate(s). Generally, the process steps and/or combination ofprocess steps for converting biopolymer containing fibrous and/orparticulate substrate into welded substrates may be referred to hereinas the “welding process” without limitation unless so indicated in thefollowing claims. In one aspect of a process, a process solvent may beapplied to one or more substrates containing natural materials. In anaspect, the process solvent may disrupt one or more intermolecular force(which intermolecular force may include but is not limited to hydrogenbonding) within at least one component of the substrate(s) containingnatural material(s).

Upon removal of a portion of the process solvent (which may beaccomplished with a reconstitution solvent as described in furtherdetail below), the fibers and/or particles within the substrate(s) maybecome fused or welded together, which may result in a welded substrate.Through testing it has been determined that the welded substrate mayhave enhanced physical properties (e.g., enhanced tensile strength) overthe original substrate(s) (prior to being subjected to processing). Thewelded substrate may also be imparted with enhanced chemical properties(e.g., hydrophobicity) or other features/functionality because of eitherthe parameters selected for the welding process itself or the inclusionof functional materials to the substrate(s) before or during the weldingprocess that converts the substrate(s) into a welded substrate.

The various processes and/or apparatuses disclosed herein may begeneralized such that the process and/or apparatuses may be configuredfor use with any number of process solvents and/or substrates (includingprocess solvents and/or substrates that are either known in academic orpatent literature as capable of fully dissolving the biopolymers ofnatural materials or those later developed). In an aspect of the presentdisclosure, the welding process may be configured such thatbiopolymer□containing substrate(s) are not fully dissolved in thetreatment process. In another aspect, robust composite materials ofvarious compositions and shapes may be produced without glue and/orresin (even in processes configured to not fully dissolve abiopolymer-containing substrate).

Generally, the welding process and/or apparatuses may be configured tocarefully and intentionally control the amount of process solvent, thetemperature, pressure, duration of process solvent exposure to naturalmaterials, and/or other parameters without limitation unless soindicated in the following claims. Additionally, the means by which aprocess solvent, reconstitution solvent, and/or drying gas can berecycled efficiently for reuse may be optimized for commercialization.As such, disclosed herein is a collection of innovative concepts andfeatures that are not obvious based on prior art. Given that naturalmaterials are generally abundant, inexpensive, and can be producedsustainably, the processes and apparatuses disclosed herein may be thearchetype for a transformative and sustainable means to manufacturetrillions of dollars per year worth of materials. This technology mayallow humankind to move forward in a way that is not restricted bylimiting resources such as petroleum and petroleum□containing materials.In an aspect, the present disclosure may achieve this result using noveland non-obvious processes and/or apparatuses configured for use withsubstrates, process solvents, and/or reconstitution not disclosed in theprior art, which may result in various novel and non-obvious endproducts.

A. Substrate Feed Zone

Referring now to the figures, wherein like reference numerals designateidentical or corresponding parts throughout the several views, FIG. 1provides schematic depiction showing various aspects of one weldingprocess that may be configured to produce a welded substrate. Thisgeneral welding process may be modified and/or optimized based on atleast a specific substrate, specific process solvent system, specificwelded substrate to be produced, functional materials utilized, and/orcombinations thereof. The welding process schematically depicted in FIG.1 is not meant to be limiting, and is for illustrative purposes onlyunless so indicated in the following claims. Additional details forcertain aspects of a welding process for producing welded substrates(e.g., specific equipment, processing parameters, process solventsystems, etc.) are provided further below, and the immediately followingexample of a welding process is intended to provide an overarchingframework highlighting certain aspects of the present disclosure thatmay be applicable to a wide range of substrates, process solvent system,reconstitution solvent systems, welded substrates, functional materials,substrate formats, welded substrate formats, and/or combinationsthereof.

Generally, a welding process may be configured such that a substratefeed zone 1 comprises a portion of the welding process at which asubstrate format(s) may be controllably fed to (enter) the weldingprocess and/or apparatuses associated therewith. The substrate feed zone1 may include equipment that creates a particular substrate format(s)from a particular substrate material or mixture of substrate materials.Alternatively, the substrate feed may be configured to deliver rolls ofpremade substrate formats. Substrates may be pushed or pulled throughthe substrate feed zone 1. Substrate may ride a powered conveyor system.Substrates may be fed through the substrate feed zone 1 by anextrusion-type screw. Accordingly, the scope of the present disclosureis not limited by whether, and/or how the substrate moves in thesubstrate feed zone 1, and/or whether the substrate remains stationaryand the equipment and/or other components of the welding process movewith respect to the substrate unless so indicated in the followingclaims.

Substrates may contain additional functional materials that may be addedto the substrate within the substrate feed zone 1. Equipment andinstrumentation may be utilized to monitor and control at least thetemperature, pressure, composition, and/or feed rate of materials withinthe substrate feed zone 1. Generally, the substrate or multiplesubstrates may move from the substrate feed zone 1 to the processsolvent application zone 2.

In an aspect of a welding process according to the present disclosureconfigured for use with certain 1D substrates (e.g., yarn and/or similarsubstrates), it may be advantageous to include an apparatus that appliesa stress to the substrate before it enters the welding process. Byapplying a predetermined stress to the substrate in advance of enteringthe fiber welding process, weak sections of the substrate may be brokenand exposed. The apparatus may also be configured with a mechanism thatties a knot to reestablish a continuous substrate. The net result isthat a welding process so configured may locate and fix weak sections ofsubstrate so as to limit down time. This apparatus may be a standalonemachine to improve certain substrates long in advance of performingwelding processes. Alternatively, this apparatus can be integrateddirectly into the substrate feed zone 1.

B. Process Solvent Application

In a process solvent application zone 2, one or more process solventsmay be applied to a substrate(s) by immersion, wicking, painting, inkjetprinting, spraying, etc. or by any combination thereof as the substratemoves through the process solvent application zone 2. Process solventmay include functional materials and/or molecular additives, both ofwhich are described in further detail below.

In an aspect, a process solvent application zone 2 may be configuredwith additional equipment that adds functional material(s) to thesubstrate separately from the process solvent. Equipment andinstrumentation may be utilized to monitor and control at least thetemperature and/or pressure of process solvent, the substrate, and/orthe atmosphere during process solvent application. Equipment andinstrumentation that monitors and controls the composition, amount,and/or rate of process solvent applied may be utilized. Process solventmay be applied to specific locations or to the entire substratedepending on the method of process solvent application.

In aspects of a welding process for producing a welded substrate usingextrusion, a die may terminate the process solvent application zone 2. Awelding process so configured may also include equipment that forms a1D, 2D, or 3D shape from loose substrate to which process solvent hasbeen applied as the substrate moves through the process solventapplication zone 2. Generally, the optimal configuration of a solventapplication zone 2 may be dependent at least upon the substrate format,choice of process solvent and/or process solvent system, and apparatusesused to apply the process solvent. These parameters may be configured toachieve a desired amount of viscous drag. “Viscous drag” as used hereindenotes the balance between process solvent and/or process solventsystem viscosity and mechanical (e.g., pressure, frictions, shear, etc.)forces that apply the process solvent and/or process solvent system intothe substrate. In some cases, the optimal viscous drag is configured toresult in a welded substrate having consistent properties throughout,and in other cases the optimal viscous drag is configured to result in amodulated welded substrate as discussed in further detail below.

In an aspect of a welding process according to the present disclosureconfigured for use with certain 1D substrates (e.g., yarn and/or similarsubstrates), it may be advantageous to employ a properly sized,needle-like orifice that may be designed to properly apply processsolvent (and thereby affect the viscous drag) to the substrate toproduce the desired properties of a welded substrate. Process solventmay be controllably metered into the device while substratesimultaneously may be moved through the orifice. At least thetemperature, flow rate and flow characteristics of process solvent,and/or substrate feed rate may be monitored and/or controlled to impartdesired properties in the finished welded substrate. The orifice size,shape, and configuration (e.g., diameter, length, slope, etc.) may bedesigned to limit or add to the stress to the substrate as processsolvent is applied thereto as discussed in further detail belowregarding FIGS. 6A-6C. This design consideration may be particularlyimportant for fine yarns or yarns that have not been combed to removeshort fiber.

The specific configuration of the process solvent application zone 2 maybe dependent at least on the specific chemistry used for the processsolvent and/or process solvent system. For example, some processsolvents and/or process solvent systems are efficacious to swell andmobilize biopolymers at relatively cold temperatures (i.e., LiOH-urea atapproximately −5° C. or below) others (i.e., ionic liquids, NMMO, etc.)are efficacious at relatively high temperatures. Certain ionic liquidsbecome efficacious above 50 C while NMMO may require temperaturesgreater than 90 C. Additionally, the viscosity of many process solventsand/or process solvent systems may be a function of temperature, suchthat the optimal configuration of various aspects of a process solventapplication zone 2 (or other aspects of welding process) may bedependent on the temperature of the process solvent application zone 2,process solvent itself, and/or process solvent system. That is, when aspecific process solvent and/or process solvent system is efficacious ata low temperature and is also relatively viscous at that lowtemperature, the equipment used to apply the process solvent and/orprocess solvent system to the substrate must be designed to accommodatethose temperatures and viscosity. Within the efficacious temperaturerange of a given process solvent and/or process solvent system, furtherrefinement of the temperature within that range, chemistry (e.g.,addition and/or ratio of co-solvents, etc.) of the process solventand/or process solvent system, configuration of apparatuses associatedwith the process solvent application zone 2, etc. may be made to resultin the appropriate amount of viscous drag which appropriately appliesprocess solvent to the substrate in way that results in a wettedsubstrate having the desired properties for remaining steps in thewelding process. However, the specific operating temperature in theprocess solvent application zone 2 in no way limits the scope of thepresent disclosure unless so indicated in the following claims.

C. Process Temperature/Pressure Zone

Upon the application of process solvent to substrate, the wettedsubstrate may enter a welding process zone of at least controlledtemperature, pressure, and/or atmosphere (composition) for a controlledamount of time. Equipment and instrumentation may be utilized tomonitor, modulate, and/or control at least the temperature, pressure,composition, and/or feed rate of process wetted substrate within thesubstrate feed zone 1. In particular, temperature may be controlledand/or modulated by utilizing chillers, convective ovens, microwave,infrared, or any number of other suitable methods or apparatuses.

In one aspect, the process solvent application zone 2 may be discretefrom the process temperature/pressure zone 2. However, in another aspectaccording to the present disclosure, the welding process may beconfigured such that these two zones 2, 3 into one contiguous segment.For example, a welding process configured such that a substrate may beimmersed in and moving through a process solvent bath for a particulartime and under controlled temperature and pressure conditions wouldcombine the process solvent application zone 2 and the processtemperature/pressure zone 3. Generally, the process solvent applicationzone 2 and process temperature/pressure zone 3 together may beconsidered a welding zone.

In aspects of a welding process according to the present disclosurewhere extrusion is performed, a die may be included within or at the endof the process temperature/pressure zone 3. Other aspects of a weldingprocess according to the present disclosure may also include equipmentthat forms a 1D, 2D, or 3D shape from loose substrate to which processsolvent has been applied and which has moved through the processtemperature/pressure zone 3.

D. Process Solvent Recovery Zone

Process solvents may be separated from the substrate within the processsolvent recovery zone 4. In an aspect, a process solvent may containsalt that has little or no vapor pressure. To remove process solvent (atleast a portion of which process solvent may be comprised of ions) fromthe substrate, a reconstitution solvent may be introduced. Uponapplication of a reconstitution solvent to the process wetted substrate,process solvent may move out of the substrate and into thereconstitution solvent. Although not required, in some aspects thereconstitution solvent may flow in a direction opposite to the movementof substrate so that the minimal amount of reconstitution solvent isrequired to recover process solvent using minimal time, space, andenergy where applicable.

In an aspect of a welding process configured according to the presentdisclosure, the process solvent recovery zone 4 may also be a bath, aseries of baths, or series of segments where reconstitution solventflows opposed or across the process wetted substrate. Equipment andinstrumentation may be utilized to monitor and control at least thetemperature, pressure, composition, and/or flow rate of reconstitutionsolvent within the process solvent recovery zone 4. Upon exiting thiszone 4, the substrate may be wetted with the reconstitution solvent.

In an aspect, it may be optimal to configure a process solvent systemwith an ionic liquid process solvent in combination with a molecularadditive and to configure the reconstitution solvent such that it ischemically similar to or chemically identical to the molecular additive.For process solvents comprised of ionic liquids, it may be beneficial toselect a molecular additive comprised having a relatively low boilingpoint but a relatively high vapor pressure. Additionally, it may bebeneficial for such molecular additives to be generally polar aprotic(as polar protic solvents generally may be more difficult to separatefrom ionic liquids and also tend to decrease the efficacy of ionicliquid-containing solvent systems), such as, but not limited to unlessindicated in the following claims, acetonitrile, acetone, and ethylacetate. For process solvents comprised of aqueous hydroxides (e.g.,LiOH), it may be advantageous to select a reconstitution solvent that iscomprised of water, which is polar protic. Configuring a welding processwith a molecular additive that is chemically similar to or chemicallyidentical to the reconstitution solvent may be beneficial to theeconomics of the welding process as it may simply the equipment and/orenergy and/or time required for at least the process solvent recoveryzone 4, solvent collection zone 7, and solvent recycling 8.Additionally, as you raise the temperature of the reconstitution solventand/or process solvent recovery zone 4, the time required forreconstitution may be greatly reduced, which may result in smalleroverall length of the welding process and associated equipment, whichmay in turn reduce the complexity and/or variation in substrate tensionand ability to control volume consolidation (as explained in furtherdetail below).

Alternatively, a welding process may be configured with a reconstitutionsolvent makeup and temperature that yields a welded substrate havingspecific attributes. For example, in one welding process utilizing aprocess solvent comprised of EMIm OAc and a reconstitution solventcomprised of water, the temperature of the water may affect theattributes of the welded yarn substrate as described in further detailbelow.

E. Drying Zone

Reconstitution solvent may be separated from the substrate within thedrying zone 5. That is, the reconstituted wetted substrate may beconverted into a finished (dried) welded substrate in the drying zone 5.Although not required, in one aspect, the drying gas may flow in adirection opposite to the movement of the reconstituted wetted substrateso that the minimal amount of drying gas may be required while dryingthe reconstituted wetted substrate via removal of the reconstitutionsolvent using minimal time, space, and/or energy where applicable.Equipment and instrumentation may be utilized to monitor and control atleast the temperature, pressure, composition, and/or flow rate of gaswithin the drying zone 5.

The drying zone 5 may be configured such that during the drying processstep, “controlled volume consolidation” is observed in the substrate,process wetted substrate, reconstituted substrate, and/or weldedsubstrate. “Controlled volume consolidation” as used herein denotes theparticular way in which the finished welded substrate shrinks in volumeand/or conforms to a specific form factor upon drying and/orreconstitution. For example, in one dimensional substrates such as ayarn, controlled volume consolidation can happen either as the diameterof the yarn is reduced and/or as the length of the yarn is reduced.

Controlled volume consolidation can be limited in one or multipledirections/dimensions by appropriately constraining at least thereconstituted wetted substrate during the drying process. Moreover, theamount and type of process and/or reconstitution solvent utilized, themethod of process and/or reconstitution solvent application (includingdegree and type of viscous drag, etc.) can affect the degree to which areconstituted wetted substrate will attempt to shrink upon drying. Forexample, in a 1D substrate (e.g., yarn, thread), controlled volumeconsolidation can be limited to only reduction of the diameter byconfiguring the draying zone 5 such that the substrate is subjected toan appropriate amount of tension during one or more steps of the weldingprocess (particularly the process solvent recovery zone 4, drying zone5, and/or welded substrate collection zone 6). In similar manner, in theexample of a two-dimensional, sheet-type substrate, proper tension andpinning of the substrate at one or more steps of the welding process(particularly the process solvent recovery zone 4, drying zone 5, and/orwelded substrate collection zone 6) can constrain the controlled volumeconsolidation to only effect substrate thickness and not change the area(length and/or width) of the substrate. Alternatively, the sheet-typesubstrate may be allowed to undergo controlled volume reduction in oneor more dimensional directions.

Controlled volume consolidation may be facilitated and/or limited byspecialized equipment in the drying zone 5 that holds the reconstitutedwetted substrate as it dries in order to control the directionality bywhich the substrate shrinks or to force the finished welded substrate tophysically comply with a particular shape or form. For example, a seriesof rollers that prevent a cardboard□substitute type product fromshrinking along the length or width of the roll, but that allow thematerial to contract in thickness. Another example is a mold onto whicha reconstituted wetted substrate may be pressed so that it may take onand hold a particular 3D shape as it dries.

In one aspect of a welding process according to the present disclosure,the drying zone 5 may be configured such that the reconstituted wettedsubstrate may experience a pressure less than ambient pressure, and maybe exposed to a relatively low amount of drying gas. In such aconfiguration, reconstituted wetted substrate may be freeze dried. Thistype of drying may be advantageous for preventing or minimizing theamount of shrinkage that occurs as the reconstitution solvent sublimes.

In an aspect of a welding process according to the present disclosurewherein the reconstitution solvent employed is benign (e.g., water),then the drying zone 5 may be omitted such that the reconstituted wettedsubstrate may move straight to collection. For example, reconstitutedwetted substrate configured as yarn might be rolled up on a collectionreel and then air dried after and/or during collection.

F. Welded Substrate Collection Zone

The welded substrate collection zone 6 may be the portion of the weldingprocess where welded substrates (e.g., finished composites) arecollected. In certain aspects of the present disclosure, the weldedsubstrate collection zone 6 may be configured as a roll of materials(e.g., a coil of yarn, cardboard□substitute, etc.). The welded substratecollection zone 6 may employ saws or stamps that cut sheets and/orshapes from, for example, welded substrate configured as a compositeextrusion. In an aspect, automated stacking equipment may be utilized topackage bundles of finished composites. Additionally, in the example ofa 1D welded substrate that is wound and packaged, the method of windingand packaging may be configured to affect one or more variablesaffecting the viscous drag of the welding process.

In an aspect of a welding process according to the present disclosureconfigured for use with certain 1D substrates (e.g., yarn and/or similarsubstrates), it may be advantageous to employ an apparatus that may rollthe welded substrate into a coil over a cylindrical or tube-likestructure either immediately after the process solvent application zone2 or immediately after the process temperature/pressure zone. Theapparatus may be used to produce a three-dimensional, tube-likestructure from a one-dimensional substrate prior to the substrateentering the process solvent recovery zone 4. In so doing, the substratemay conform to the new tube-like shape. It is contemplated that such anapparatus may be especially useful when employed in a welding processconfigured at least in part to produce functional composite materialsfrom yarn substrates that contain functional materials (e.g., catalystsembedded within yarns) without limitation unless so indicated in thefollowing claims.

In another aspect of a welding process according to the presentdisclosure configured for use with certain 1D substrates (e.g., yarnand/or similar substrates), it may be advantageous to employ anapparatus that may knit or weave the substrate immediately after theprocess solvent application zone 2 or immediately after the processtemperature/pressure zone 3. The apparatus may be configured to producea fabric structure from the substrate prior to entering the processsolvent recovery zone 4. Such an apparatus may be configured such thatthe welding process may produce 2D fabrics with unique properties thatcannot be achieved through other means of manufacturing.

In yet another aspect of a welding process according to the presentdisclosure configured for use with certain 1D substrates (e.g., yarnand/or similar substrates), it may be advantageous to employ anapparatus that may produce a coiled package of yarn (e.g., a traversecam). Such an apparatus may be configured to roll welded substrate intocoil-like packages that may be unwound at a later time without becomingentangled.

G. Solvent Collection Zone

As described above, process solvent may be washed from the processwetted substrate by the reconstitution solvent within the processsolvent recovery zone 4. Accordingly, in one aspect the reconstitutionsolvent may mix with various portions of the process solvent (e.g., ionsand/or any molecular constituents, etc.). This mixture (or relativelypure process solvent or reconstitution solvent) may be collected at anappropriate point within the solvent collection zone 7. In one aspect,the collection point may be positioned near the entry point of theprocess wetted substrate. Such a configuration may be especially usefulfor configurations utilizing counter flow of reconstitution solvent withrespect to process wetted substrate due to the concentration of processsolvent constituents within the process wetted substrate being lowest ata point wherein the concentration thereof in the reconstitution solventis lowest. This configuration may result in less reconstitution solventusage as well as ease separating and recycling the process andreconstitution solvents.

In the solvent collection zone 7, various equipment and instrumentationmay be utilized to monitor and control at least the temperature,pressure, composition, and flow rate of reconstitution solvent, processwetted substrate, and/or reconstitution wetted substrate.

H. Solvent Recycling

In an aspect, a welding process according to the present disclosure maybe configured to collect the mixed solvent (e.g., part reconstitutionsolvent and part process solvent), relatively pure process solvent,and/or relatively pure reconstitution solvent may be collected andrecycled. Various equipment and/or methods may be used to separate,purify, and/or recycle reconstitution solvent and process solvent. Anyknow method(s) and/or apparatus(es) or those later developed may be usedto separate the reconstitution solvent and the process solvent, and theoptimal equipment for such separation will depend at least on thechemical compositions of the two solvents. Accordingly, the scope of thepresent disclosure is in no way limited by the specific apparatus(es)and/or method(s) used to separate the reconstitution solvent and processsolvent, which apparatuses and/or methods may include but are notlimited to simple distillation of a co-solvent and/or ionic liquid(e.g., the method disclosed in U.S. Pat. No. 8,382,926), fractionaldistillation, membrane-based separations (such as pervaporation andelectrochemical cross-flow separation), and supercritical CO₂ phase.After the reconstitution solvent and process solvent have beenadequately separated, the respective solvents may be recycled to theappropriate zone within the process.

I. Mixed Gas Collection

As previously described above, reconstitution solvent engaged with thereconstituted wetted substrate may be removed therefrom in the dryingzone 5. In an aspect, either mixed gas comprised of a carrier drying gaswith a portion of reconstitution solvent gas therein or reconstitutionsolvent gas may be collected from the drying zone 5. Equipment and/orinstrumentation may be used to monitor and control at least thetemperature, pressure, composition, and flow rate of gases collected.

J. Mixed Gas Recycling

As gas(es) are collected, they may be sent to equipment that separatesand recycles either the carrier drying gas, reconstitution solvent, orboth. In one aspect, this equipment may be a single or multiple stagecondenser technology. Separation and recycling may also include gaspermeable membranes and other technologies without limitation unless soindicated in the following claims. Depending on the choice of carriergas, it may be vented to the atmosphere or returned to the drying zone5. Depending on the choice of reconstitution solvent it may be eitherdisposed of, or recycled to the process solvent recovery zone 4.

Generally, a welding process configured according to aspects of thepreceding description may be configured to convert a natural fiberand/or particle containing substrate into a finished, welded substratein a continuous and/or batch welding process utilizing a substrate feedzone 1, process solvent application zone 2, process temperature/pressurezone 3, process solvent recovery zone 4, drying zone 5, and weldedsubstrate collection zone 6. In certain aspects, it may be critical tomonitor and control the amount, composition, time, temperature, andpressure of the process solvent relative to the substrate.

3. Welding Process Examples (FIGS. 1 & 2)

Referring to FIG. 1, a substrate may move with a controlled rate by anysuitable method and/or apparatus (e.g., pushing, pulling, conveyorsystem, screw extrusion system etc.). In an aspect, a substrate may movethrough the substrate feed zone 1, process solvent application zone 2,process temperature/pressure zone 3, process solvent recovery zone 4,drying zone 5, and/or welded substrate collection zone 6 in a continuousfashion. However, the specific order in which a substrate passes fromone zone 1, 2, 3, 4, 5, 6 to another may vary from one welding processto the next, and as mentioned previously in some aspects of a weldingprocess according to the present disclosure a substrate may move througha welded substrate collection zone 6 prior to moving to a drying zone 5.Additionally, in some aspects the substrate may remain relativelystationary while solvents and/or other welding process components and/orapparatuses move. At any point in a welding process configured accordingto the present disclosure automation, instrumentation, and/or equipmentmay be employed to monitor, control, report, manipulate, and/orotherwise interact with one or more component of the welding processand/or equipment thereof. Such automation, instrumentation, and/orequipment includes but is not limited to (unless otherwise indicated inthe following claims) those that may monitor and control forces (e.g.,tension) exerted on the substrate, process wetted substrate,reconstituted substrate, and/or the finished welded substrate.Generally, the various process parameters and apparatuses employed for awelding process may be configured to control the amount of viscous dragfor the desired process solvent application. The various processparameters and apparatuses employed for a welding process may beconfigured to perform controlled volume consolidation to yield a weldedsubstrate having the desired attributes, form factor, etc.

Still referring to FIG. 1, in an aspect of a welding process depictedtherein, a process solvent loop may be defined as process solventapplication zone 2, process temperature/pressure zone 3, process solventrecovery zone 4, solvent collection zone 7, and solvent recycling 8,after which the process solvent may again move to the process solventapplication zone 2.

In another aspect of a welding process depicted in FIG. 1, areconstitution solvent loop may be defined as two separate loops—one forreconstitution solvent in the liquid state and another forreconstitution solvent in a gaseous state. The liquid reconstitutionsolvent loop may be comprised of the recovery zone 4, solvent collectionzone 7, and solvent recycling 8, after which the reconstitution solventmay again move to the process solvent recovery zone 4. The gaseousreconstitution solvent loop may be comprised of the process solventrecovery zone 4, drying zone 5, mixed gas collection 9, and mixed gasrecycling 10, after which the reconstitution solvent may again move tothe process solvent recovery zone 4. In an aspect of a gaseousreconstitution solvent loop, a portion of the reconstitution solvent maybe carried into the drying zone 5 by the reconstituted wetted substrate.

In a welding process according to the present disclosure wherein acarrier gas is used, the carrier gas may be recycled in a loop comprisedof drying zone 5, mixed gas collection 9, and mixed gas recycling 10,after which the drying gas may again move to the drying zone 5.

For commercialization, recycling process solvent, reconstitutionsolvent, carrier gas, and/or other welding process components may becritical. Further, any loop for a process solvent, reconstitutionsolvent, carrier gas, and/or other welding process component may includea buffer tank, storage vessel, and/or the like without limitation unlessso indicated in the following claims. As described in further detailbelow, the specific choice of substrate, process solvent, reconstitutionsolvent, drying gas, and/or desired finished welded substrate maygreatly impact at least the optimal welding process steps, orderthereof, welding process parameters, and/or equipment to be usedtherewith.

In light of the foregoing description, it will be apparent that awelding process according to the present disclosure may be separatedinto discrete processing steps. For example, one welding process may beconfigured in the order of substrate feed zone 1, process solventapplication zone 2, process temperature/pressure zone 3, and weldedsubstrate collection zone 6, followed by storing or aging the processwetted substrate for some time and then at a later time performing thefunctions of the process solvent recovery zone 4 and/or drying zone 5.Again, in certain aspects one or more processing steps may be omitted(e.g., the drying zone 5 when water is used as the reconstitutionsolvent). Furthermore, in certain aspects of a welding process accordingto the present disclosure, some processing steps may occursimultaneously, or the end of one processing step may naturally flowinto the beginning of another processing step as described in furtherdetail below.

Referring now to FIG. 2, which provides a schematic depiction showingvarious aspects of another welding process that may be configured toproduce a welded substrate, the welding process depicted therein issimilar to that depicted in FIG. 1, but in FIG. 2 the processtemperature/pressure zone 3 and process solvent recovery zone 4 may beblended into one contiguous welding process step rather than constitutediscrete welding process steps. Additionally, the welding processdepicted in FIG. 2 may employ two mixed gas collection zones 9 and thesolvent collection zone 7 may primarily collect process solvent suchthat the solvent recycling may be primarily adapted for process solvent(as opposed to a mixture of process solvent and reconstitution solvent).It is contemplated that such a configuration may provide certainadvantages related to equipment simplification and/or consolidation. Invarious welding processes according to the present disclosure, a processsolvent recovery zone 4 may be configured such that the reconstitutionsolvent and process wetted substrate move opposite with respect to oneanother as depicted schematically in FIG. 2A.

In an aspect of a welding process configured according to FIG. 2, thewelding process may be adapted for use wherein the reconstitutionsolvent is a component of the process solvent (e.g., a process solventcomprised of a mixture of 3-ethyl-1-methylimidizolium acetate withacetonitrile and a reconstitution solvent of acetonitrile). In such aconfiguration, some advantages of which are described in further detailbelow, a portion of the volatile acetonitrile could be captured andseparated from the process solvent at any point in the welding processat which process solvent is present via any suitable method and/orapparatus including but not limited to a controlled low pressureenvironment, carrier gas, and/or combinations thereof without limitationunless so indicated in the following claims. Generally,3-ethyl-1-methylimidizolium acetate in sufficient concentration maydisrupt intermolecular forces in certain substrates (e.g., the hydrogenbonding in cellulose). Accordingly, the combination of the processtemperature/pressure zone 3 and process solvent recovery zone 4 mayconstitute a general welding process zone at any location therein wherethe mole ratio of 3-ethyl-1-methylimidizolium acetate to acetonitrile isappropriate to cause the desired characteristics of disruption ofintermolecular forces in the substrate. This general welding processzone may also constitute all or a portion of a reconstitution andrecycling zone if proper flow rates, temperatures, pressures, otherwelding process parameters, etc. are properly designed and/orcontrolled.

Still referring to FIG. 2, the substrate may again move through awelding process with a controlled rate using any suitable method and/orapparatus (e.g., pushing, pulling, conveyor system, screw extrusionsystem, etc.) without limitation unless so indicated in the followingclaims. In an aspect, the substrate may move through the substrate feedzone 1, process solvent application zone 2, a combination of a processtemperature/pressure zone 3 and a process solvent recovery zone 4,drying zone 5, and/or welded substrate collection zone 6 in a continuousfashion. However, the specific order in which a substrate passes fromone zone 1, 2, 3, 4, 5, 6 to another may vary from one welding processto the next, and as mentioned previously in some aspects of a weldingprocess according to the present disclosure a substrate may move througha welded substrate collection zone 6 prior to moving to a drying zone 5.Additionally, in some aspects the substrate may remain relativelystationary while solvents and/or other welding process components and/orapparatuses move. At any point in a welding process configured accordingto the present disclosure automation, instrumentation, and/or equipmentmay be employed to monitor, control, report, manipulate, and/orotherwise interact with one or more component of the welding processand/or equipment thereof. Such automation, instrumentation, and/orequipment includes but is not limited to (unless otherwise indicated inthe following claims) those that may monitor and control forces (e.g.,tension) exerted on the substrate, process wetted substrate,reconstituted substrate, and/or the finished welded substrate.

Still referring to FIG. 2, in an aspect of a welding process depictedtherein, a process solvent loop may be defined as process solventapplication zone 2, a combination of a process temperature/pressure zone3 and a process solvent recovery zone 4, (process) solvent collectionzone 7, after which the process solvent may again move to the processsolvent application zone 2.

In another aspect of a welding process depicted in FIG. 2, areconstitution solvent loop may be defined as two separate loops—one forreconstitution solvent in the liquid state and another for processsolvent in a gaseous state. The liquid reconstitution solvent loop maybe comprised of a combination of a process temperature/pressure zone 3and a process solvent recovery zone 4, and one or more mixed gascollection zones, and after which the reconstitution solvent may againmove to the combination of a process temperature/pressure zone 3 and aprocess solvent recovery zone 4. The gaseous reconstitution solvent loopmay be comprised of the drying zone 5, at least one mixed gas collection9, and mixed gas recycling 10, after which the reconstitution solventmay again move to the combination of a process temperature/pressure zone3 and a process solvent recovery zone 4. In an aspect of a gaseousreconstitution solvent loop, a portion of the reconstitution solvent maybe carried into the drying zone 5 by the reconstituted wetted substrate.

In a welding process according to the present disclosure wherein acarrier gas is used, the carrier gas may be recycled in a loop comprisedof drying zone 5, at least one mixed gas collection 8, and mixed gasrecycling 10, after which the drying gas may again move to the dryingzone 5.

In an aspect of the welding process depicted in FIG. 2, the weldingprocess may also include a carrier volatile capture loop, which loop maybe comprised of the combination of a process temperature/pressure zone 3and a process solvent recovery zone 4, at least one mixed gas collection8, and mixed gas recycling 10. In an aspect of a welding processaccording to the present disclosure wherein the reconstitution solventmay be present in the process solvent, the welding process may includemore than one carrier gas loops. For example, if the process solventwere configured as a mixture of 3-ethyl-1-methylimidizolium acetate withacetonitrile, acetonitrile could serve as the reconstitution solvent.

It is contemplated that for certain welding processes, it may beadvantageous to include one or more electronically controlled valves,drive wheels, and/or substrate guides (e.g., yarn guides that provide anew loose end or broken yarn end to be (re)threaded through an apparatusof a welding process with little or no human intervention). It iscontemplated that a welding process so configured may reduce the boththe amount of downtime for the welding process and the amount of humancontact required for the welding process compared to a welding processnot so configured.

In an aspect, a process solvent recovery zone 4 may be configured suchthat the process wetted substrate may be collected while reconstitutionsolvent is introduced to the process wetted substrate. For example, in awelding process configured to use yarn and/or thread as a substrate, awinding mechanism can be placed at the end of the processtemperature/pressure zone 3. In an aspect, the winding mechanism can beenclosed such that as reconstitution solvent is introduced to theprocess wetted substrate (e.g., by spraying), the process wettedsubstrate may be washed continuously and converted into a reconstitutedwetted substrate. Such a configuration can lead to a greatsimplification of the overall welding process in that the substrate neednot run continuously from the process solvent recovery zone 4 to thedrying zone 5. Instead, the reconstitution can happen more as a batchprocess, whereby a specific portion of substrate (e.g., cylinder or ballof yarn rolled into a continuous untangled entity) may be produced andreconstituted. At a certain point, the reconstituted wetted package canbe transferred into a secondary reconstitution process and/or sent tothe drying zone to remove the reconstitution solvent.

In another aspect, a welding process configured as a continuous processwherein the substrate may move continuously from the processtemperature/pressure zone 3 to the process solvent recovery zone 4 tothe drying zone 5. In such a configuration, the tension forces on thesubstrate may be additive, and can sometimes cause breakage, which maybe highly problematic to the efficiency of the welding process.Accordingly, a welding process may be configured with rollers, pulleys,and/or other suitable methods and/or apparatuses to aid the movement ofthe substrate through the welding process to mitigate and/or eliminatebreakage.

Additionally and/or alternatively, a welding process may be configuredto reduce the amount of tension the substrate experiences during all ora portion of the welding process. In such a configuration, the substratemay move through a specified space in which reconstitution solvent maybe applied to the process wetted substrate (e.g., via an applicator asdescribed in further detail below) instead of moving the substratethrough individual tubes (which also may be expensive and makerethreading more difficult). Such a configuration may be used with anysubstrate format, and it is contemplated that such a configuration maybe especially useful for 1D substrates (e.g., yarns and/or threads)either alone or in a sheet-like configuration comprised of multipleindividual substrates positioned adjacent one another and/or 2Dsubstrates (e.g., fabrics and/or textiles). A process solvent recoveryzone 4 so configured may mitigate and/or eliminate friction on thesubstrate and/or buildup of unnecessary tension, which may increase thethroughput of substrate through the welding process.

4. Solvent Application Zone: Apparatuses/Methods

Various aspects of the concept of viscous drag as it pertains to processsolvent application are shown in FIG. 6A, which provides a cutaway viewof an apparatus that may be used in a process solvent application zone2. Note that natural fiber substrates may have variance in the densityof fiber per unit cross-section and/or area. It is possible to modulateprocess solvent application to the substrate such that the ratio of massof process solvent applied per unit mass of substrate is wellcontrolled. This can be accomplished by actively monitoring the varianceof the substrate with appropriate sensors and using this data to controlthe speed of process solvent pumps and/or the speed of the substratethrough the process solvent application zone and/or the process solventcomposition. Alternatively, it is possible to engineer points of viscousdrag that apply the appropriate squeezing force and/or shear on aprocess wetted substrate in order to control the process solventapplication. The design of viscous drag can include small volumes thatallow process solvent to appropriately pool. In so doing, the processsolvent can be applied such that the mass ratio of process solvent tosubstrate maybe either held at a stable value or modulated within adesired tolerance. (Modulated fiber welding processes are described inmore detail below.)

In one aspect of a welding process (either modulated or non-modulatedwithout limitation unless so indicated in the following claims), thewelding process may be configured to apply a process solvent via aninjector. In one configuration of the injector, the injector may becomprised of a narrow tube with two inlets and one outlet. Substratecomprised of yarn (or other 1D substrate) may enter one inlet andprocess solvent may flow into the other inlet. The process wettedsubstrate (yarn with process solvent applied thereto) may exit theoutlet. An injector may be comprised of additional inlets for addingfunctional materials, additional process solvent, and/or othercomponents. As previously described above herein, the process wettedsubstrate (e.g., yarn, thread, fabric, and/or textile with processsolvent applied) may be passed to the process temperature/pressure zone3 after the process solvent application zone 2.

As shown in FIG. 6A, an injector 60 may be configured for use witheither a 1D or 2D substrate (e.g., yarn or fabric, respectively). Aninjector may include a substrate input 61 opposite a substrate outlet64. An injector 60 may be configured to deliver controlled quantities ofprocess solvent to one or more substrates (which substrates may becomprised of fabric, textiles, yarn, thread, etc.) and generally may befurther configured to appropriately distribute that process solventaround and within the substrate. For example, in a non-modulated weldingprocess it may be desirable to evenly distribute the process solventthroughout a given substrate, whereas in a modulated welding process itmay be desirable to vary the distribution of process solvent in a givensubstrate.

One example of an injector 60 so configured may be comprised of a shellhaving T-shaped cross section, wherein a 1D or 2D substrate may enterand exit the injector through a relatively straight path. A processsolvent may be pumped through a secondary input, which may be in a pathgenerally perpendicular to that of the substrate. Such a configurationof an injector 60 is shown in FIG. 6A.

As shown in FIG. 6A, the injector 60 may include a substrate input 61into which raw substrate (yarn, thread, fabric, textile, etc.) may befed. The injector 60 may also include a process solvent input 62 that isin fluid communication with a portion of the substrate input 61.Accordingly, process solvent may flow into the injector 60 through theprocess solvent input 62 and engage the substrate adjacent anapplication interface 63. This portion of the injector 60 may constitutethe process solvent application zone 2 as previously described above.

When configured for use with a 1D substrate, the portion of the injector60 from the substrate input 61 to the substrate outlet 64 may beconfigured like a tube. When configured for use with a 2D substrate,that portion of the injector 60 may be configured as two plates spacedfrom one another (similar to the apparatus shown in FIG. 6C, which isdescribed in further detail below). The substrate and/or process wettedsubstrate may be positioned in the space between the two plates 82, 84,and at least one plate 82, 84 may be formed with at least one processsolvent inputs 63.

A substrate outlet 64 may be engaged with a portion of the injector 60generally opposite the substrate input 61. In one configuration of aninjector 60, a substrate outlet 64 may be non-linear, as shown in FIG.6A. The non-linear substrate outlet 64 may be configured to physicallycontact the exterior of a process wetted substrate to direct the processsolvent to a desired portion of the substrate, which physical contactmay be accomplished at least at one or more inflection points, which mayprovide a shearing force and/or compression force to the substrate.Additionally, a non-linear substrate outlet 64 may be configured tophysically contact the exterior of a process wetted substrate. Thisphysical contact may be an aspect of achieving the desired viscous dragof a given welding process. Physical contact may be configured to addadditional smoothness to the exterior of the process wetted substrate toeliminate and/or reduce the amount of short hair/fibers on the resultingwelded substrate. Physical contact with a process wetted substrate mayalso improve heat transfer from a process solvent to a substrate and/orprocess wetted substrate, which heat transfer may shorten the requiredprocessing time (e.g., welding time), thereby shortening the length ofthe welding chamber and reducing the space required for the equipmentassociated with a given welding process. Physical contact with thesubstrate and/or process wetted substrate may be accomplished via amultitude of design considerations (to create inflection points in one,two, and/or three dimensions), including but not limited to varying thedimensions (e.g., diameter, width, etc.) and/or curvature of thesubstrate input 61, application interface 63, and/or substrate outlet64, and/or combinations thereof, positioning another structure adjacenta substrate and/or process wetted substrate (e.g., wiper, baffle,roller, flexible orifice, etc.) without limitation unless so indicatedin the following claims.

Alternatively, an injector may be configured such that it is Y-shaped,and/or one or more injectors may be configured with multiple stages toadd process solvents, functional materials, and/or other components atspecific locations and under specific conditions at one or more pointsduring a welding process.

In one aspect, an injector may be utilized in conjunction with a yarnreceiver, wherein both the injector and the yarn receiver may beconfigured to slide on a rail system and/or other suitable method and/orapparatus allowing selective placement of the injector and yarn receiveralong one dimension. A welding process configured to allow selectivemanipulation of one or more injectors and/or yarn receivers in at leastone dimension (e.g., by allowing them to slide along the length of arail system) may reduce the time and/or resources required to re-threadyarn and/or thread at any point in the welding process (and inparticular, through the process temperature/pressure zone 3) compared towelding processes without such selective manipulation, and maysimultaneously enable a high(er) density of welding processes to bemultiplexed within a relatively small space.

For example, in a welding process configured with ‘n’ number of yarnsbeing processed simultaneously, only the outer yarns are relatively easyto access. In the event an individual yarn breaks, this can makerethreading difficult. By having a removable, track mounted injector atthe start of the substrate feed zone 1, process solvent application zone2, and/or process temperature/pressure zone 3, one (a person orautomation) can easily remove the injector, and move it to the end of agroup of substrates positioned in the welding process for rethreading.It is contemplated that for some applications it may be advantageous toconfigure the injector in a clam-shell design, but can also be anassembly of tubes without limitation unless so indicated in thefollowing claims. That is, the injector can be designed in a‘clam-shell’ configuration wherein at least two pieces of materialenclose a yarn or group of yarns. This allows yarn to be initiallyloaded into the welding process machinery more easily and also isamenable to designing systems that provide appropriate viscous drag formultiple ends of yarn simultaneously. As any particular injector isremoved, the other injectors may slide down one position to close theexisting gap and create a new gap that is positioned at one edge of theapparatus(es) for the welding process. Working in concert, a series ofreceiving units positioned at or near the end of any given process zonemay also move accordingly, such that individual yarns move into each oftheir new positions, respectively.

The optimal configuration of a receiving unit may vary from one aspectof a welding process to the next, and may depend on at least the size ofthe substrate, process solvent used, and/or type of substrate used. Inone aspect, a receiving unit may be comprised of a simple pulley or yarnguide that directs yarn into the process solvent recovery zone 4 and/ordrying zone 5. In another aspect, receiving units can be significantlymore complex (i.e., winding mechanisms) depending on how the weldingprocess is configured, such as the configuration of the process solventapplication zone 2, process temperature/pressure zone 3, process solventrecovery zone 4, and/or drying zone 5.

Another apparatus illustrating the concept of viscous drag as itpertains to process solvent application is shown in FIG. 6B. Theapparatus, which may be configured as a tray 70, as shown in FIG. 6B maybe configured for use with both 1D and 2D substrates. As shown, the tray70 may be configured with one or more substrate grooves 72 formed in asurface of the tray 70. The tray 70 may have a plurality of grooves 72such that process solvent may be applied to multiple substrates (1Dsubstrates shown in FIG. 6B) simultaneously.

Although the grooves 72 shown in FIG. 6B may be linear, in other aspectsof a tray 70 the grooves may be non-linear in a manner correlative tothe injector 60 shown in FIG. 6A and the plates shown in FIG. 6C. Thatis, the tray 70 and grooves 72 thereof may be configured such that aportion of the tray 70 and/or grooves physically contact a portion ofthe substrate (which physical contact may constitute a consideration foroptimizing viscous drag). Physical contact may be accomplished via amultitude of design considerations (to create inflection points, shearforces, compression, etc. in one, two, and/or three dimensions),including but not limited to varying the depth of a groove 72,cross-sectional shape of a groove 72, width of a groove 72, curvature ofa groove 72, and/or combinations thereof, and/or positioning anotherstructure adjacent a substrate and/or process wetted substrate (e.g.,wiper, baffle, roller, flexible orifice, etc.) without limitation unlessso indicated in the following claims. without limitation unless soindicated in the following claims.

In one configuration, the spacing of the 1D substrates can be reduced tothe point where many substrates essentially move together in atwo-dimensional plan or a ‘sheet’ as further illustrated in FIG. 6C. Inanother configuration, the width of a groove 72 may be selected to allowa generally two-dimensional sheet of fabric and/or textile to move withrespect to the tray 70 through the groove 72.

Generally, the process solvent may be continuously supplied to eachgroove 72 and/or a portion thereof such that as the substrate movesalong the groove 72, process solvent is applied thereto so as to createa process wetted substrate. A groove 72 may be flooded with processsolvent (in which configuration the groove 72 may function similar to aprocess solvent bath), and/or process solvent may be applied to asubstrate adjacent a leading edge of the groove 72 and then properlywiped along an exterior portion of the substrate as the substrate movestoward a trailing edge of the groove. In one configuration of a weldingprocess, a tray 70 may be angled with respect to the horizontal toutilize gravitational force on the process solvent, and the optimalangle may depend at least on the speed and direction of substratemovement with respect to the tray 70.

The optimal configuration of each groove 72 will vary from oneapplication of a welding process to the next, and is therefore in no waylimiting to the scope of the present disclosure unless so indicated inthe following claims. When configured for multiple 1D substrates thatare laterally spaced from one another by a distance equal to or greaterthan the average diameter of each substrate, it is contemplated that thewidth of a groove 72 may be approximately equal to the depth there, andeach dimension may be approximately 10% greater than the averagediameter of the substrate.

The optimal cross-sectional shape of each groove 72 may also vary fromone welding process to the next. For example, in some applications itmay be optimal for the cross-sectional shape of a groove 72 (or at leastthe bottom portion thereof) to approximate and/or match thecross-sectional shape of the substrate (or at least a portion thereof).For example, when configured for use with a substrate comprised of a 1Dyarn or thread, a groove 72 may be configured with a U-shapedcross-section. When configured for use with a substrate comprised of a2D fabric or textile, a groove 72 may be configured with a width muchgreater (e.g., 10 times, 20 times, etc.) than its depth. However, thespecific cross-sectional shape, depth, width, configuration, etc. of agroove 72 is in no way limiting to the scope of the present disclosureunless so indicated in the following claims.

A configuration of a process solvent application zone 2 configured foruse with a plurality of 1D substrates (which may be comprised of threadsand/or yarns) approximating a 2D sheet is shown in FIG. 6C. The processsolvent application zone 2 may employ a first plate 82 and a secondplate 84 with corresponding curvature to create at least three points ofphysical contact (i.e., inflection points) in at least one dimension. Inother configurations, the plates 82, 84 may be differently configured tocreate greater or fewer inflection points in one or more dimensions,wherein the inflection points are configured to applying more resistanceto the substrate and/or process wetted substrate or less resistancethereto. Physical contact may be accomplished via a multitude of designconsiderations (to create inflection points in one, two, and/or threedimensions), including but not limited to varying distance between theplates 82, 84, curvature of either plate 82, 84, whether the concavityof a curve in one plate 82, 84 corresponds to the convexity of a curvein the other plate 82, 84, and/or combinations thereof, and/orpositioning another structure adjacent a substrate and/or process wettedsubstrate (e.g., wiper, baffle, roller, flexible orifice, etc.) withoutlimitation unless so indicated in the following claims.

In another configuration, the viscous drag may be variable based atleast on the relative positions of one or more structural components.For example, and referring specifically to FIGS. 6D, 6E, and 6F, platesmay be configured such that inner edges thereof overlap with one anotherby an adjustable amount. When the inner edges overlap by a greateramount, such as shown in FIG. 6E, a substrate positioned between thecorresponding plates may experience greater physical resistance tomovement relative to the plates. When the inner edges overlap by alesser amount, such as shown in FIG. 6E, a substrate positioned betweenthe corresponding plates may experience less physical resistance tomovement relative to the plates. Adjustable overlap of as applied to awelding process configured for use with multiple 1D substratespositioned adjacent one another is shown in FIG. Adjustability of therelative positions of the plates may allow for multiple process solventsto be used with a given apparatus and/or for a given apparatus to beemployed in welding processes configured to produce welded substrateshaving differing attributes.

As described above relating to the concept of viscous drag and FIGS. 6A& 6B, the plates 82, 84 in FIGS. 6C, 6D, and 6E may be configured tocontrol process solvent application. The designs shown in FIGS. 6A-6Eare not meant to be limiting in any way unless so indicated in thefollowing claims, and any suitable structure and/or method may be usedto properly apply process solvent to a substrate and/or to properlyinteract with the substrate and/or process wetted substrate to achievethe desired attribute for the welded substrate. That is, the appropriateamount of viscous drag can be achieved by any number of structures(which structures can be moveable to preset tolerances to achieve thedesired process solvent application effect) or methods, including andnot limited to rollers, shaped edges, smooth surfaces, number and/ororientation of inflection points, resistance to relative movement,varying temperatures, etc. and unless otherwise indicated in thefollowing claims.

In another configuration of a welding process (either modulated ornon-modulated without limitation unless so indicated in the followingclaims), the welding process may be configured to apply a processsolvent via an applicator. In one configuration of the applicator, theapplication may be correlative to those used in inkjet printers, screenprinting techniques, spray guns, nozzles, dip tanks, or inclined trays,and/or combinations thereof (some of which are shown at least in FIGS.6A-6F and described in detail above) without limitation unless soindicated in the following claims. It is contemplated that the weldingprocess may be configured such that when a substrate (e.g., yarn,thread, fabric, and/or textile) is properly positioned with respect toan applicator, the applicator directs process solvent to the substrate,thereby creating process wetted substrate. Such a welding process may beconfigured such that process solvent and/or functional materials may beapplied in a multidimensional pattern, which may be useful for embossinga pattern into a textile and/or fabric using the welding process. Such apattern may constitute a modulated welding process (as described infurther detail below), wherein the modulation is a result of at leastthe application of process solvent to a substrate. As previouslydescribed above herein, the process wetted substrate (e.g., yarn,thread, fabric, and/or textile with process solvent applied) may bepassed to the process temperature/pressure zone 3 after the processsolvent application zone 2.

Referring generally to FIGS. 11A-11D, in a configuration of a modulatedwelding process using an injector or an applicator, the modulatedwelding process may allow for variation of the composition of theprocess solvent in real-time at least by controlling at least pump flowrate(s) of individual process solvent constituents. A modulated weldingprocess may be configured to allow variation of the ratio of processsolvent to substrate (either on a volume or mass basis) at least bycontrolling either the pump flow rate(s) of process solvent constituentsand/or by variable rate of substrate movement through at least theprocess solvent application zone 2. A schematic overview for such amodulated welding process configured for use with a 2D substrate isshown in FIG. 11B and for use with a 1D substrate is shown in FIG. 11D,all of which are described in further detail below.

Referring now to FIG. 11A (2D substrate) and 11C (1D substrate), amodulated welding process may be configured to allow the temperature tobe modulated by any suitable method and/or apparatus, including but notlimited to microwave heating, convection, conduction, radiation, and/orcombinations thereof without limitation unless so indicated in thefollowing claims. A modulated welding process may be configured to allowmodulation of the pressure, tension, viscous drag, etc. experienced bythe substrate and/or process wetted substrate. The combined effects ofmodulation of various parameters of a modulated welding process(including but not limited to the conditions previously mentioned) canproduce unique welded substrates comprised of welded yarns that exhibitunique dye and/or coloration patterns as well as unique feel and/orfinish.

Conversely, as previously described, a welding process may be configuredto yield welded substrates with consistent characteristics (e.g.,coloration, size, shape, feel, finish, etc.) throughout by configuringthe welding process to run very consistently without modulation ofvarious process parameters (e.g., process solvent composition, processsolvent to substrate mass ratio, temperature, pressure, tension, etc.).

In one aspect of a welding process configured for scaled production ofwelded substrates from multiple 1D substrates positioned adjacent oneanother (e.g., a sheet-like structure comprised of multiple yarnspositioned adjacent on another), multiple ends of yarn can be moved as asheet, which may provide improved economies of scale for some weldingprocesses. The same concepts and principles regarding welding processesconfigured for 2D substrates (e.g., fabrics, paper substrates, textiles,and/or composite mat substrates) as disclosed herein may be applicableto multiple 1D substrates positioned adjacent one another.

By way of analogy, a welding process configured to weld multiple 1Dsubstrates in a sheet-like configuration may be similar as to a weldingprocess configured to weld a 2D substrate (e.g., a fabric and/ortextile), but it is contemplated that the welding process for 1Dsubstrates may have some important differences. Such differences mayinclude, but are not limited to, accommodations (e.g., yarn guides) tomitigate and/or eliminate the likelihood of one substrate becomingentangled with itself and/or another substrate (e.g., individual yarns),and process solvent application may utilize either injectors forindividual yarns or groups of yarns. Alternatively, a welding processmay be configured such that no injector is required if process solventis applied directly to the 1D substrates in a sheet-like configurationby spraying, dropping, wicking, dunking, and/or otherwise introducingprocess solvent in a controlled rate onto the sheet-like configuration.Accordingly, in accordance with the present disclosure variousapparatuses and/or methods may be configured to yield a highlymultiplexed welding process that scales to mass production.

A. Low-Moisture Substrates

Cellulosic (i.e., cotton, linen, regenerated cellulose, etc.) andlignocellulosic (i.e., industrial hemp, agave, etc.) fibers are known tocontain significant (5 to 10% by mass) moisture. Moisture levels in, forexample, cotton can vary from roughly 6 to 9% depending on theenvironmental temperature and relative humidity. In addition, IL-basedsolvents such as 3-ethyl-1-methylimidazolium acetate (“EMIm OAc”),3-butyl-1-methylimidizolum chloride (“BMIm Cl”), and1,5-diaza-bicyclo[4.3.0]non-5-enium acetate (“DBNH OAc”) are oftencontaminated with water either during syntheses and/or by absorptionfrom the environment. Moreover, molecular component additives to theprocess solvent, such as acetonitrile (ACN) are also hydroscopic.Generally, the presence of water negatively impacts the efficacy of pureionic liquids and IL-based solvents with molecular component additivesto dissolve biopolymer substrates. However, it may be difficult and/orresource intensive to remove the last few percentage points (by mass) ofwater from these solutions. The cost of ionic liquids and IL-basedsolvents may be directly correlated with their purity, and inparticular, with moisture content. Accordingly, a welding process may beconfigured to utilize low-moisture substrates to increase theperformance of welded substrates as well as improve the overall economyof such a welding processes.

In addition to aiding welding processes using ionic liquid and IL-basedprocess solvents, low-moisture substrate materials can also aid fiberwelding processes that utilize N-methylmorpholine N-oxide (NMMO) as aprocess solvent as well. Generally, NMMO solutions that are 4% to 17% bymass water are capable of cellulose dissolution and may be utilized inLyocell-type processes. Utilizing sufficiently dry biopolymer-containingsubstrate materials means that welding processes may be configured withprocess solvents having a water content at the upper end (˜17% by mass)and still efficiently and economically produce the desired weldedsubstrate. In a welding process configured to use a process solventcomprised of ionic liquids that are moisture sensitive (e.g.,3-butyl-1-methylimidizolium chloride (“BMIm”) Cl,3-ethyl-1-methylimidazolium acetate (“EMIm OAc”),1,5-diaza-bicyclo[4.3.0]non-5-enium acetate (“DBNH OAc”), etc.), theamount of moisture in the substrate may affect the rate at which weldingoccurs, and therefore associated process parameters and apparatusdesign. In welding processes configured to use process solvents that areless moisture sensitive (e.g., NMMO, LiOH-urea, etc.) than certain ionicliquids disclosed above, the advantages of a relatively dry substrateare reduced and/or eliminated.

Accordingly, experiments have shown the surprising results of weldingprocesses configured to use biopolymer substrates that have beenartificially dried to low moisture states (<5% by mass) prior towelding. Low-moisture substrates may speed up the welding processeswhile simultaneously improving the quality (i.e., strength, lack ofstray fiber, etc.) of welded substrates. Even more surprising is thatwater is removed from ionic liquids and IL-based process solvents by thestrong desiccating nature of low-moisture biopolymer substrates. In oneaspect, water may be removed from ionic liquids and IL-based processsolvents that are reconstituted by non-aqueous media, for example, ACN.In fact, low-moisture substrates purify both process solvents andreconstitution solvents of water as they are continuously recycledthrough the fiber welding process.

Low-moisture substrate materials may be obtained by preconditioningmaterials in sufficiently dry (and sometimes warm, for example ˜40 to80° C.) atmospheres for controlled time prior to being introduced into awelding process that utilizes a process solvent comprised of, forexample, moisture-sensitive ionic liquid. It may be important thatbiopolymer-containing substrates be held in controlled climates prior toand during a welding process. Furthermore, intentionally introducingwater to specific regions of space within a biopolymer substrate mayserve to retards welding in that location and may allow for anothermethod to modulate a welding process, several methods for which aredescribed herein below.

Generally, experiments have shown that a welding process configured toutilize an artificially dry substrate (e.g., a substrate that has beendried prior to introduction into the substrate feed zone 1 and/or asubstrate that is dried in all or a portion of the substrate feed zone1) yields surprising new synergies that improve the economics of thewelding process and/or the welded substrates produced thereby. Forexample, drying cotton substrates to less than 5% moisture by mass candramatically improve the consistency and/or control of welding whenutilizing BMIm Cl+ACN solutions (or other moisture-sensitive processsolvent systems). Moreover, upon continuously utilizing dry cottonsubstrates and upon recycling the process solvent multiple times,experiments have shown that the water content of both process solvents(e.g., BMIm Cl+ACN) and reconstitution solvents (e.g., ACN) may bedecreased so long as equipment is appropriately sealed from externalwater (e.g., water in the atmosphere). The desiccating nature of thedried cotton substrate increases as the moisture content decreases. Inother words, cotton that is 3% by mass water is more desiccating thancotton that is 4% by mass water.

5. Attributes of Welded Substrates Produced at Commercial Scale

The foregoing description discloses attributes of various new materials(which materials generally are referred to as 1D welded substrates and2D welded substrates) that may be produced using a welding processaccording to the present disclosure. The following attributes are noveland non-obvious in light of the prior art because these attributes areonly present in the following materials when those materials aremanufactured in large quantities (e.g., on a commercial scale). Thematerial attributes may allow for manufacturing cost reductions intextiles as well as enabling new uses for natural substrate (e.g.,cotton) containing textiles.

It is well known that petroleum-based materials (e.g., polyester, etc.)may be configured to produce both filament-type yarns and staple fiberyarns. As used herein, the term “staple fiber yarns” denotes yarns thatare spun from fibers having relatively short, discrete lengths (staplefiber). However, prior to the processes and apparatuses disclosedherein, there was no filament-type yarn derived from natural staplefibers wherein the natural staple fibers (and, consequently, afilament-type yarn derived therefrom) retain a measure of their originalattributes, structure, etc. of the staple fiber. The processes andapparatuses disclosed herein may be differentiated from all priorteaching regarding Rayon, Modal, Tencel®, etc. wherein manmade staplefiber is produced via full dissolution and/or derivatization ofcellulose and then extruded (which full dissolution may be accomplishedusing NMMO, ionic-liquid based systems, etc.). In the cases of Rayon,Modal, Tencel®, etc., cellulosic precursors are fully dissolved anddenatured in such a way that it is virtually impossible to determine thecellulosic source (e.g., beechwood tree pulp, bamboo pulp, cotton fiber,etc.) from which the staple fiber was derived. By contrast, weldedsubstrates produced according to the present disclosure retain certainattributes, characteristics, etc. of the staple fiber in the substrateas described in further detail below. In retaining these nativeattributes, characteristics, etc., the present methods and apparatusesuse a relatively small amount of process solvent per unit of weldedsubstrate relative to the prior art, and even while enabling newfunctionalities (e.g., decreased water retention, increased strength,etc.) traditionally associated with synthetic and/or petroleum-basedfilament-type yarns. These new welded substrates and functionalitiesthereof, in turn, enable entire new fabric applications not possiblewith the prior art. The degree to which welded substrates express and/orexhibit these functionalities may depend at least on the configurationof the welding process used to manufacture the welded substrate.

Included within 1D welded substrates that may be manufactured using awelding process according to the present disclosure are non-plied‘singles’ and plied yarns and threads as well as “welded yarnsubstrates.” Although the foregoing attributes and examples may beattributable to welded yarn substrates, the scope of the presentdisclosure is not so limited and the term “1D welded substrate” is notso limited unless indicated in the following claims.

Generally, welded yarn substrates are differentiated from conventionalraw yarn substrates counterparts at least by: (1) the amount of emptyspace between the individual fibers that make up yarns, as welded yarnsubstrates are significantly more dense than conventional raw substratecounterparts having a mean diameter that is roughly 20% to 200% smallerthan conventional yarns that have an equivalent weight of biopolymersubstrate per unit length; and (2) welded yarn substrates do notgenerally have much if any loose fiber at their surface and thus do notshed (and the amount and characteristics of any loose fiber at theirsurface may be manipulated during the welding process). Specificempirical data for welded substrates and the corresponding natural fibersubstrate are explained in detail below.

Generally, when loose fiber is present at the surface of a welded yarnsubstrate, at least some portion of the loose fiber is welded to thewelded yarn substrate. That is to say, fiber is not really loose to beseparated from the welded yarn substrate, but is instead anchored to acore of welded fibers within the middle of the welded yarn substrate.This may occur if the process solvent tends to migrate to the center ofthe substrate yarns during the welding process. However, the weldingprocess may be configured to limit or promote welding within either thecore or at the outside portion of a yarn substrate by varying at leastthe composition of process solvent and/or to adding multiple processsolvent compositions at different times.

The two attributes listed above alone and/or in combination may bedesirable/advantageous for a number of reasons. For example, a cottonyarn that does not shed can be knit with Spandex (also known as Lycra orelastane) or other synthetic fibers more efficiently because the amountof loose fiber (lint) is reduced and/or eliminated so that it does notcause problems with knitting machines. Lint and shedding is a knownproblem in the textile industry in that it causes imperfections intextiles and down time for equipment that must be cleaned and/or fixedbecause of lint build up. Static cling causes loose fiber to naturallyadhere to synthetic fibers and is problematic. Welded yarn substratessignificantly reduce these issues because shedding is eliminated and/ormitigated. Fabrics and/or textiles produced from a welded yarn substrateand Spandex (or Lycra, etc.) may be useful as active wear (e.g., shirts,pants, shorts, etc.) and/or undergarments (e.g., underwear, bras, etc.)without limitation unless so indicated in the following claims.

Welded yarn substrates may be manufactured such that they are strongerthan their conventional raw substrate counterparts (of similar weightper unit length as well as per unit diameter). Welded yarn substratescan eliminate the need for “slashing” (or “sizing”) during theproduction of woven materials (e.g., denim). Yarn slashing is theprocess by which sizing (e.g., starch) is applied to a yarn (most oftenprior to weaving) in order to make it strong enough to undergo theweaving process. Upon a woven textile being produced, the sizing must bewashed away. Yarn slashing not only adds expense, but is also resource(e.g., water) intensive. Slashing is also not permanent in that uponremoval of sizing, yarns return to their original (lessor) strength. Incontrast, the welding process may be configured to strengthen theresulting welded yarn substrate compared to conventional yarn such thatslashing is not required, thus saving expense and resources while addinga more permanent improvement of strength.

Skew is a fabric condition in which the warp and weft yarns, althoughstraight, are not at right angles to each other. This originates fromthe fact that conventional yarns are twisted during manufacture andtherefore biased to untwist (unravel). Fabrics manufactured from weldedyarn substrates may have the attribute that they skew much lessaggressively than fabrics manufactured from conventional raw substratecounterparts because welded yarn substrates may have the attribute thatthey cannot untwist (unravel) after the welding process becauseindividual fibers may be fused/welded.

Welded yarn substrates may convert low-twist yarns, yarns with shorterfiber length, and/or yarns produced from lower-quality fiber (e.g.,fiber of different denier) into higher-value, stronger welded yarnsubstrates. For example, in conventional yarns, the twist factor isstrongly correlated with strength. More twists per unit length costsmore money. Low-twist yarn used as a substrate for a welding processaccording to the present disclosure may result in a welded yarnsubstrate that is much stronger than the conventional yarn substratebecause of how the welding process may be configured to fuse individualfibers.

Welded yarn substrates can convert uncombed yarns into higher value,stronger welded yarn substrates. In conventional yarns, the combingprocess removes short fiber from sliver to yield higher strength yarnfurther down the manufacturing chain. Combing is machine and energyintensive and adds cost to the manufacture of yarn. Welded yarnsubstrates produced from a substrate comprised of sliver that was notcombed may result in a welded yarn substrate that is much stronger thanthe conventional yarn substrate because the welding process may beconfigured to fuse short and long fibers to enhance strength. Thewelding process may be configured to produce stronger yarn atsignificant cost savings.

Textiles produced from welded yarn substrates may have that attributethat they hold their shape and do not have the tendency and/orpropensity to shrink as much as fabrics manufactured from conventionalyarns. Because a welding process may be configured to result in weldedyarn substrates having significantly less (little to no) loose fiber attheir surfaces compared to conventional yarn, textiles can be producedfrom the welded yarn substrates with a much lower fill factor than thoseproduced from conventional yarn, and in ways that are akin to what isdone with single filament synthetic yarns (e.g., polyester).

Referring now to FIGS. 12A & 12B, which provide SEM images of a rawdenim 2D substrate, and the resulting welded 2D substrate (using the rawsubstrate from FIG. 12A as a starting material), respectively, increasedengagement between adjacent fibers may be readily visually observed forthe welded substrate compared to the raw substrate. The increasedengagement between adjacent fibers may provide various attributes to thewelded substrate not present in the raw substrate, including but notlimited to increased stiffness, lower moisture absorption, and/orincreased rate of drying.

Referring now to FIGS. 12C & 12D, which provide SEM images of a raw knit2D substrate, and the resulting welded 2D substrate (using the rawsubstrate from FIG. 12C as a starting material), respectively, increasedengagement between adjacent fibers may be readily visually observed forthe welded substrate compared to the raw substrate. The increasedengagement between adjacent fibers may provide various attributes to thewelded substrate not present in the raw substrate, including but notlimited to increased stiffness, lower moisture absorption, and/orincreased rate of drying.

In a welding process configured to act on a 2D substrate (e.g., awelding process configured to produce a welded substrate similar to thatshown in FIG. 12B or 12D), adding solubilized polymer (to the substrateand/or process solvent) and/or increasing the pressure on the processwetted substrate during the process temperature/pressure zone 3 maypromote increased interlayer adhesion when making multiple layeredand/or laminate composites. Generally, the degree to which the substrateis welded (e.g., high, moderate, low) may affect the flexibility of theresulting welded substrate.

In addition to increased burst strength, fabric such as that shown inFIGS. 12B and 12D may exhibit an enormous increase in the score of thefabric when tested using the Martindale Pill Test. For example, a fabriccomprised of raw yarn substrate that would score 1.5 or 2 on this testincreases to 5 if that fabric is subjected to a welding process thatperformed even a moderate amount of the appropriate welding on thesubstrate.

Welded yarn substrates may have superior moisture wicking and absorptionproperties compared to conventional yarns, specifically conventionalcotton yarn. As such, welded yarn substrates may dry more quickly thanconventional yarns and thereby provide associated cost and resourcereduction. Coupled with less tendency and/or propensity to shrink,fabrics constructed of welded yarn substrates may have much greaterutility in activewear (e.g., sportswear), intimate apparel (e.g.,lingerie), etc. where the combination of water management and lack ofshrinkage are important attributes.

Textiles produced from welded yarn substrates may be configured to bemuch stronger for their weight compared with textiles produced fromconventional yarns. Because the mean diameters of welded yarn substratesmay be less than the mean diameters of conventional yarns for a givenweight yarn, the burst strength of textiles manufactured using weldedyarn substrates is observed to increase significantly.

Additionally, textiles produced from welded yarn substrates may beconfigured to allow wide variations and controllable results in the“hand” of the textile (e.g., feel, texture, etc.) and finish because awelding process may be configured to add a coating to the substrateand/or adjust the depth of process solvent penetration in the substrate.For example, in an aspect of a welding process, the welding process maybe configured to coat a yarn substrate with solubilized cellulose as afilm, which may greatly change the smoothness of the outside of theresulting welded yarn substrate as compared to the conventional rawsubstrate counterpart.

Included within 2D welded substrates that may be manufactured using awelding process according to the present disclosure are welded substratecardboard, welded substrate paper-type, and/or welded substratepaper-substitute materials. Although the foregoing attributes andexamples may be attributable to welded substrate paper-substitutematerials, the scope of the present disclosure is not so limited and theterm “2D welded substrate” is not so limited unless indicated in thefollowing claims. Generally, the materials and/or attributes thereof for2D welded substrates may allow for manufacturing cost reductions ofpaper-type and construction materials as well as enabling new uses forthese materials compared to conventional materials.

Generally, welded substrate paper-substitute materials may bedifferentiated from conventional raw substrate counterparts at least bythe fact that welded substrate paper-substitute materials may containsignificant amounts (e.g., greater than 10% by mass or volume) oflignocellulosic materials. Conversely, conventional cardboard and otherpaper material contain refined cellulose pulp with little or nolignocellulosic materials. A welding process according to the presentdisclosure may be configured to produce a welded substratepaper-substitute material containing significant amounts oflignocellulosic materials. Lignocellulosic materials may serve as bothlow cost filler and/or strengthening (reinforcement) agents. Thesewelded substrate paper-substitute materials may allow fordifferentiation within the paper and cardboard industry that is notpresently observed. For example, low-cost thermal sleeves for coffeecups, pizza, and other food delivery/packaging boxes, boxes for shippingapplications, clothing hangers, etc. These welded substratepaper-substitute materials may be transformative in that the cost ofpulping (e.g., Kraft pulping) is eliminated. Two-dimensional and/orthree-dimensional welded substrates may be useful in applicationsutilizing paper and/or cardboard by providing stronger, and/or lightermaterials such as diapers, cardboard substitute, paper substitute, etc.without limitation unless so indicated in the following claims.

Some of the standard textile/fabric tests that have been used to verifyand quantify the superior attributes of welded substrates compared totheir raw substrate counterparts include, but are not limited to: (1)AATCC 135 (laundering test fabric); (2) AATCC 150 (laundering testgarment); (3) ASTM D2256 (single end yarn test); (4) ASTM D3512 (pillingrandom tumble); and (5) ASTM D4970 (Martindale pill test). This list isnot exhaustive, and other tests may be mentioned herein. Accordingly,the scope of the present disclosure is not limited by the specific testand/or quantitative data for a particular raw substrate or weldedsubstrate unless so indicated in the following claims.

6. Specific Aspects of Various Welding Processes and Properties ofResulting Welded Substrates

What follows is data for welded substrates manufactured using variousmethods and apparatuses according to the present disclosure. However,nothing in the following specific examples (e.g., process parametersused for producing the various welded substrates, the attributes,dimensions, configuration, etc. of the welded substrate) disclosed belowis meant to limit the scope of the present disclosure unless soindicated in the following claims, and rather are for illustrativepurposes.

One process for producing a welded substrate may be configured to use aprocess solvent comprised of EMIm OAc with ACN for application to asubstrate comprised of raw 30/1 ring spun cotton yarn (‘30 single’,tex=19.69 weight yarn). A scanning electron microscope (SEM) image ofsuch a substrate is shown in FIG. 7B, and an SEM image the resultingwelded substrate is shown in FIG. 7C. Table 1.1 shows some of the keyprocessing parameters used to manufacture the welded substrate in FIG.7C. In this configuration, process solvent application was accomplishedvia pulling the substrate through a 33-inch long tube, wherein the tubewas filled with process solvent. Accordingly, such a configuration doesnot result in discrete process solvent application zone 2 At the end oftube, a flexible orifice (e.g., squeegee) was designed to physicallycontact the process wetted substrate to remove a portion of the processsolvent from the exterior surface of the process wetted substrate and todistribute the process solvent properly with respect to the substrate.

A schematic representation of a welding process is shown in FIG. 7A, andthat welding process may be configured to produce the welded substrateshown in FIG. 7C. The welding process shown in FIG. 7A may be configuredaccording to the various principles and concepts previously describedherein related to FIGS. 1, 2, & 6A-6E regarding viscous drag, processsolvent application, physical contact with process wetted substrate,etc. For brevity, the aspects of this welding process related to processsolvent recovery zone 4, solvent collection zone 7, solvent recycling 8,mixed gas collection 9, and mixed gas recycling zones 10 are omitted.Note that viscous drag was achieved by co-optimization of the processsolvent composition, the temperature, the flexibility and size of thesqueegee orifice, et cetera. Volume controlled consolidation of thewelded substrates was limited to yarn diameter reduction only bycontrolling the linear tension on the process welded substrate and/orreconstituted wetted substrate during drying thereof in the drying zoneand by the collection method of winding the welded substrate undercontrolled tension conditions. However, with 2D or 3D substrates, volumecontrolled consolidation of the welded substrate may limit the tensionon a process wetted substrate, reconstituted wetted substrate, etc. inother dimensions, which may require controlling at least a first lineartension, a second linear tension, and/or a third linear tension.

TABLE 1.1 Pull Welding Temperatures Rate Zone Solv. Ratio (° C.) (m/min)Time (sec) (g/g) Solvent Type Process solvent 5.3 10.0 Approx. 4 EMImOAc:ACN application 1:2 (Mole Ratio) zone/process pressure temperaturezone: 65

Table 1.1 shows some of the key processing parameters used tomanufacture the welded substrate in FIG. 7C utilizing the weldingprocess shown in FIG. 7A. Note that in Table 1.1, “welding zone time”refers to the duration in which the substrate was positioned in theprocess solvent application zone 2 and process temperature/pressure zone3. This time represents roughly an order of magnitude reduction ofwelding time compared with the prior art. There are, of course, manyprocesses that have been divulged for which samples are treated forminutes to hours. However, the prior art does not disclose partialsolubilization-type processes that are able to achieve desired effectsin such short durations. This significant reduction in welding time wasonly possible by co-optimizing process solvent chemistry with hardwareand control systems engineered to achieve the desired effects. That isto say, by combining chemistry and hardware in ways that achieve theappropriate viscous drag and controlled volume consolidation to achievesurprising new effects in the finished welded yarn substrates. A plot ofthe stress in grams versus percent-elongation applied to both arepresentative raw yarn substrate sample and a representative weldedyarn substrate is shown in FIG. 7D, wherein the top curve is the weldedyarn substrate and the bottom trace is the raw.

Still referring to Table 1.1, “pull rate” refers to the linear rate atwhich the substrate moves through the welding process (which affectsviscous drag), and “solvent ratio” refers to the mass ratio of processsolvent to substrate.

Table 1.2 provides various attributes of the welded substrate shown inFIG. 7C (as performed on approximately 20 unique specimens of weldedyarn substrate), which attributes were collected using an Instron brandmechanical properties tester operating in tensile testing modeapproximating ASTM D2256. As used in Table 1.2, breaking strengthdenotes the average absolute force in grams at which the weldedsubstrates. The normalized breaking strength is grams converted tocenti-Newtons normalized by the weight of the raw yarn substrate (whichfor this sample was 19.69 tex). Percent elongation denotes displacementdivided by gauge length times 100 at which breakage occurred.

TABLE 1.2 Norm. Breaking Breaking Strength Strength Elongation (g)(cN/dtex) (%) 375 1.86 4.2

Another process for producing a welded substrate may be configured touse a process solvent comprised of EMIm OAc with ACN for application toa substrate comprised of raw 30/1 ring spun cotton yarn. A schematic ofsuch a welding process is shown in FIG. 8A. The welding process shown inFIG. 8A may be configured according to the various principles andconcepts previously described herein related to FIGS. 1, 2, & 6A-6Eregarding viscous drag, process solvent application, physical contactwith process wetted substrate, etc. For brevity, the aspects of thiswelding process related to process solvent recovery zone 4, solventcollection zone 7, solvent recycling 8, mixed gas collection 9, andmixed gas recycling zones 10 are omitted. In this example, aspects ofthe apparatus for use with the welding process were specificallyconfigured to increase the rate at which substrate comprised of yarncould be moved through the process. In specific, by separating theprocess solvent application 2 from the process temperature/pressure zone3 using an injector 60 device analogous to that described in FIG. 6A.

Table 2.1 shows some of the key processing parameters used tomanufacture the welded substrate in FIG. 8C using the welding processdepicted in FIG. 8A. The process parameters for each column heading inTable 2.1 are the same as those previously described regarding Table1.1. In this welding process, the temperatures of the process solventapplication zone 2 and process temperature/pressure zone 3 were held atdifferent values to co-optimize both the desired amount of viscous dragand promote increased process solvent efficacy. In addition, byachieving process solvent application using a metering pump and applyingviscous drag at key points throughout the process solvent applicationzone 2, it was possible to limit the frictional forces (e.g., shearing)on the yarn substrate to achieve greater tension control. This had theeffect of additionally aiding the volume controlled reduction of theyarn substrate diameter. The overall design enabled faster totalthroughput than the previous example and is evident by comparing Table1.1 with Table 2.1.

A scanning electron microscope (SEM) image of a substrate comprised ofraw 30/1 ring spun cotton yarn that may be used with welding process ofFIG. 8A is shown in FIG. 8B. An SEM image of the resulting weldedsubstrate is shown in FIG. 8C. Table 2.1 shows some of the keyprocessing parameters used to manufacture the welded substrate in FIG.8C.

TABLE 2.1 Welding Solv. Pull Rate Zone Ratio Temperatures (° C.) (m/min)Time (sec) (g/g) Solvent Type Process solvent 14.4 11.0 2.85 EMImOAc:ACN application zone: 78 1:2 (Mole Ratio) process pressuretemperature zone: 74

Table 2.2 provides various attributes of the welded substrate shown inFIG. 8C produced using the parameters described in Table 2.1. Theattributes were averaged as performed on approximately 20 uniquespecimens of welded yarn substrates, which attributes were collectedusing an Instron brand mechanical properties tester operating in tensiletesting mode approximating ASTM D2256. The mechanical property for eachcolumn heading in Table 2.2 are the same as those previously describedregarding Table 1.2. A plot of the stress in grams versuspercent-elongation applied to both a representative raw yarn substratesample and a representative welded yarn substrate sample is shown inFIG. 8D, wherein the top curve is the welded yarn substrate and thebottom trace is the raw.

TABLE 2.2 Norm. Breaking Breaking Strength Strength Elongation (g)(cN/dtex) (%) 395 1.96 4.9

Another process for producing a welded substrate may be configured touse a process solvent comprised of EMIm OAc with ACN for application toa substrate comprised of raw 30/1 ring spun cotton yarn or 10/1 open endspun cotton yarn. Such a process may be analogous to that shownschematically in FIG. 8A. Table 3.1 shows some of the key processingparameters used to manufacture a welded substrate from a substratecomprised of 10/1 open end spun cotton yarn, and Table 3.2 providesvarious attributes of the welded substrate and the raw substrate using awelding process with the parameters shown in Table. 3.1. Of course,these data are illustrative for attributes of a welded substrate thatmay be accomplished via a welding process and are not meant to limit thetype of yarn substrates that can be welded and/or attributes of weldedsubstrates unless so indicated in the following claims.

Another process for producing a welded substrate may be configured touse a process solvent comprised of EMIm OAc with ACN for application toa substrate comprised of raw yarn. A perspective view of variousapparatuses that may be configured to perform such a welding process isshown in FIG. 9A. The welding process and apparatuses therefor shown inFIG. 9A may be configured according to the various principles andconcepts previously described herein related to FIGS. 1, 2, & 6A-6Eregarding viscous drag, process solvent application, physical contactwith process wetted substrate, etc. For brevity, the aspects of thiswelding process related to process solvent recovery zone 4, solventcollection zone 7, solvent recycling 8, mixed gas collection 9, andmixed gas recycling zones 10 are omitted.

A scanning electron microscope (SEM) image of a substrate that may beused with the welding process and apparatuses of FIG. 9A is shown inFIG. 9B, and an SEM image the resulting welded substrate is shown inFIG. 9C. Table 3.1 shows some of the key processing parameters used tomanufacture the welded substrate using the welding process andapparatuses shown in FIG. 9A to produce the welded substrate in FIG. 9K(which is analogous to the welded substrate shown in FIG. 9C in that itis lightly welded). The process parameters for each column heading inTable 3.1 are the same as those previously described regarding Table1.1.

Note that this welding process may configured to move multiple ends ofyarn substrate simultaneously, and that virtually all important processparameters such as process solvent flow rate, temperature, substratefeed rate, substrate tension, etc. may be adjusted. In particular, thiswelding process and apparatuses may enable the co-optimization ofviscous drag and controlled volume consolidation for particular weldedsubstrates designed for specific products. A selected number of weldedyarn substrates are shown in FIGS. 9C-9E and 9I-9M.

TABLE 3.1 Pull Welding Solv. Rate Zone Time Ratio Temperatures (° C.)(m/min) (sec) (g/g) Solvent Type Process solvent 17.3 8.9 3.0 EMImOAc:ACN application zone: 77 1:2 (Mole Ratio) process pressuretemperature zone: 77

Table 3.2 provides various attributes of the welded substrate shown inFIG. 9K produced using the parameters described in Table 3.1. Theattributes were averaged as performed on approximately 20 uniquespecimens of welded yarn substrate, which attributes were collectedusing an Instron brand mechanical properties tester operating in tensiletesting mode approximating ASTM D2256. The mechanical property for eachcolumn heading in Table 3.2 are the same as those previously describedregarding Table 1.2. A plot of the stress in grams versuspercent-elongation applied to both a representative raw yarn substratesample and a representative welded yarn substrate sample (such as thewelded substrate shown in FIGS. 9C and 9K that has been lightly welded)is shown in FIG. 9G, wherein the top curve is the welded yarn substrateand the bottom trace is the raw.

TABLE 3.2 Norm. Breaking Breaking Strength Strength Elongation (g)(cN/dtex) (%) 348 1.73 3.0

Table 4.1 shows some of the key processing parameters used tomanufacture the welded substrate using the welding process andapparatuses shown in FIG. 9A to produce the welded substrate in FIG. 9L(which is analogous to the welded substrate shown in FIG. 9D in that itis moderately welded). The process parameters for each column heading inTable 4.1 are the same as those previously described regarding Table1.1.

Note that this welding process may configured to move multiple ends ofyarn substrate simultaneously, and that virtually all important processparameters such as process solvent flow rate, temperature, substratefeed rate, substrate tension, etc. may be adjusted. In particular, thiswelding process and apparatuses may enable the co-optimization ofviscous drag and controlled volume consolidation for particular weldedsubstrates designed for specific products.

TABLE 4.1 Pull Welding Solv. Rate Zone Time Ratio Temperatures (° C.)(m/min) (sec) (g/g) Solvent Type Process solvent 18.0 8.5 3.0 EMImOAc:ACN application zone: 90 1:2 (Mole Ratio) process pressuretemperature zone: 79

Table 4.2 provides various attributes of the welded substrate shown inFIG. 9L produced using the parameters described in Table 4.1. Theattributes were averaged as performed on approximately 20 uniquespecimens of welded yarn substrate, which attributes were collectedusing an Instron brand mechanical properties tester operating in tensiletesting mode approximating ASTM D2256. The mechanical property for eachcolumn heading in Table 4.2 are the same as those previously describedregarding Table 1.2.

TABLE 4.2 Norm. Breaking Breaking Strength Strength Elongation (g)(cN/dtex) (%) 365 1.82 2.2

Table 5.1 shows some of the key processing parameters used tomanufacture the welded substrate using the welding process andapparatuses shown in FIG. 9A to produce the welded substrate in FIG. 9M(which is analogous to the welded substrate shown in FIG. 9E in that itis highly welded). The process parameters for each column heading inTable 5.1 are the same as those previously described regarding Table1.1.

Note that this welding process may configured to move multiple ends ofyarn substrate simultaneously, and that virtually all important processparameters such as process solvent flow rate, temperature, substratefeed rate, substrate tension, etc. may be adjusted. In particular, thiswelding process and apparatuses may enable the co-optimization ofviscous drag and controlled volume consolidation for particular weldedsubstrates designed for specific products.

TABLE 5.1 Pull Welding Solv. Rate Zone Time Ratio Temperatures (° C.)(m/min) (sec) (g/g) Solvent Type Process solvent 17.3 8.9 3.5 EMImOAc:ACN application zone: 110 1:2 (Mole Ratio) process pressuretemperature zone: 79

Table 5.2 provides various attributes of the welded substrate shown inFIG. 9M produced using the parameters described in Table 5.1. Theattributes were averaged as performed on approximately 20 uniquespecimens of welded yarn substrate, which attributes were collectedusing an Instron brand mechanical properties tester operating in tensiletesting mode approximating ASTM D2256. The mechanical property for eachcolumn heading in Table 5.2 are the same as those previously describedregarding Table 1.2.

TABLE 5.2 Norm. Breaking Breaking Strength Strength Elongation (g)(cN/dtex) (%) 353 1.76 1.8

A progression of the degree to which a substrate is welded is shown inFIGS. 9C-9E, all of which welded substrates may be manufactured usingthe process and apparatuses shown in FIG. 9A by varying the processparameters. In particular, the SEM data show progressive elimination ofloose hair on cotton yarns as well as varying degrees of controlledvolume consolidation for a lightly welded substrate in FIG. 9C,moderately welded substrate in FIG. 9D, and highly welded substrate inFIG. 9E. All of these welded substrates were manufactured using asubstrate comprised of raw 30/1 cotton yarn. The terms “lightly,”“moderately,” and “highly” are not meant to be limiting in any sense,but rather meant to convey a relative, qualitative aspect unlessotherwise indicated herein or in the following claims.

A test fabric produced from a lightly welded substrate (which weldedsubstrate may be analogous to those shown in FIG. 9C or 9K) is shown inFIG. 9F. The absolute attributes of fabrics knitted or woven from weldedsubstrates may vary, and may be manipulated at least via the processparameters and degree of welding performed on the welded substratescomprising the fabric. Table 6.1 shows some of the key processingparameters used to manufacture the welded substrate using the weldingprocess and apparatuses shown in FIG. 9A to produce the welded substrateused for the fabric shown in FIG. 9F. The process parameters for eachcolumn heading in Table 6.1 are the same as those previously describedregarding Table 1.1.

TABLE 6.1 Welding Solv. Pull Rate Zone Time Ratio Temperatures (° C.)(m/min) (sec) (g/g) Solvent Type Process solvent 18.0 8.5 3.0 EMImOAc:ACN application zone: 90 1:2 (Mole Ratio) process pressuretemperature zone: 79

Table 6.2 provides various attributes of the fabric comprised of threedistinct samples of lightly welded substrates such as those from FIGS.9C and 9K (using raw 30/1 ring spun yarn substrate) and for acorresponding fabric made using raw yarn substrate. The burst strengthswere determined using ASTM D3786. The column heading “Burst Strength”refers to the absolute burst strength in pounds per square inch, and thecolumn heading “Burst Strength Improve.” refers to the percentimprovement of the fabric comprised of welded yarn substrates comparedto that comprised of raw yarn substrates, which is the control.

TABLE 6.2 Burst Strength Burst Strength Yarn used in Fabric (psi)Improve. % Control (raw substrate) 60.0 — Welded A (lightly weldedsubstrate) 71.5 +19% Welded B (lightly welded substrate) 72.5 +21%Welded C (lightly welded substrate) 72.9 +21%

In addition to increased burst strength, fabric such as that shown inFIG. 9F may exhibit an enormous increase in the score of the fabric whentested using the Martindale Pill Test (ASTM D4970). For example, afabric comprised of raw yarn substrate that would score 1.5 or 2 on thistest would increase to 5 if that same raw yarn substrate was subjectedto a welding process such that it was even moderately welded.

Another progression of the degree to which a substrate is welded isshown in FIGS. 9K-9M, all of which welded substrates may be manufacturedusing the process and apparatuses shown in FIG. 9A by varying theprocess parameters as described above related to the Tables associatedwith the welding process for producing each welded substrate. Inparticular, the SEM data show progressive elimination of loose hair oncotton yarns as well as varying degrees of controlled volumeconsolidation for a lightly welded substrate in FIG. 9K, moderatelywelded substrate in FIG. 9L, and highly welded substrate in FIG. 9M. Allof these welded substrates were manufactured using a substrate comprisedof raw 30/1 cotton yarn. Some mechanical properties of the yarns shownin FIGS. 9K-9M and that shown in FIGS. 9I & 9J are shown in Table 7.1,which provides a comparison of the same mechanical properties for theraw yarn substrate. In Table 7.1, “tenacity” refers to a weightnormalized measure of strength, which is commonly used in the yarn andfiber industry.

TABLE 7.1 Degree of Welding Tenacity (cN/dtex) Elongation Raw yarn 1.244.9% Lightly welded 1.73 3.0% Medium welded 1.82 2.2% Highly welded 1.761.8% Core-shell type welding 1.89 4.2%

Generally, increased strength is observed for welded substrates ascompared to their raw substrate counterparts. As previously discussed,the fabric shown in FIG. 9F has a burst strength that is approximately30% greater than that of a similar knitted control fabric produced fromraw yarn substrate. Other improvements such as decreased time of drying(after laundering), increased abrasion resistance, and greater vibrancyof dyeing compared to raw substrate counterparts are also observed andwill be discussed in further detail below. The absolute degree to whichthese attributes are observed may be controlled at least via the processparameters (e.g., the degree and quality of the welding process). Thedegree and quality of the welding process, in turn, may be a function ofat least the co-optimization of process solvent application and viscousdrag as well as controlled volume consolidation that occurs duringvarious steps of a welding process.

Referring again to FIG. 9G, which shows a comparison ofpercent-elongation as a function of linear tension (in grams) applied toboth a raw substrate and welded substrate, welded substrates exhibitsuperior mechanical properties. The welded substrate shown in FIG. 9Cmay be considered a “core welded” substrate, wherein the term “corewelded” refers to welded substrates in which process solvent applicationand welding action have permeated the substrate relatively evenlythroughout the substrate diameter.

The welded substrate shown in FIGS. 9I and 9J may be considered a “shellwelded” substrate, wherein the term “shell welded” refers to a weldedsubstrate that has been preferentially welded on the outer exteriorsurface of the substrate (i.e., so as to create a welded shell). Asclearly shown in the center portion of the centrally positioned weldedsubstrate shown in FIG. 9J, the welded shell is distinct from aminimally/non-welded core.

This shell welded substrate may be manufactured from a substratecomprised of raw 30/1 ring spun cotton yarn utilizing the weldingprocess and apparatuses shown in FIG. 9A. Table 8.1 shows some of thekey processing parameters used to manufacture the shell welded substrateusing the welding process and apparatuses shown in FIG. 9A to producethe welded substrate in FIGS. 9I & 9J. The process parameters for eachcolumn heading in Table 8.1 are the same as those previously describedregarding Table 1.1.

Note that this welding process may configured to move multiple ends ofyarn substrate simultaneously, and that virtually all important processparameters such as process solvent flow rate, temperature, substratefeed rate, substrate tension, etc. may be adjusted. In particular, thiswelding process and apparatuses may enable the co-optimization ofviscous drag and controlled volume consolidation for particular weldedsubstrates designed for specific products.

TABLE 8.1 Welding Solv. Pull Rate Zone Time Ratio Temperatures (° C.)(m/min) (sec) (g/g) Solvent Type Process solvent 3.5 14.4 3.0 BMImCl:ACN application 1:1 (Mole Ratio) zone: 105 process pressuretemperature zone: 105

Table 8.2 provides various attributes of the welded substrate shown inFIGS. 9I & 9J produced using the parameters described in Table 8.1. Theattributes were averaged as performed on approximately 20 uniquespecimens of welded yarn substrate, which attributes were collectedusing an Instron brand mechanical properties tester operating in tensiletesting mode approximating ASTM D2256. The mechanical property for eachcolumn heading in Table 8.2 are the same as those previously describedregarding Table 1.2.

TABLE 8.2 Norm. Breaking Breaking Strength Strength Elongation (g)(cN/dtex) (%) 380 1.89 4.2

By optimizing various process parameters (e.g., process solvent tosubstrate ratio, temperature, pressure, etc., and the resulting efficacyof the process solvent) and viscous drag, it is possible to control thedepth to which the substrate is welded in a dimension from the exteriorof the substrate to the interior thereof. That is, a welding process maybe configured to preferentially weld the outer regions of the substratesuch that the substrate core is not welded to the same degree as theexterior thereof. This has the effect of increasing strength compared tothe raw substrate while also often retaining elongation properties ofthe raw substrate, and thus results in increased toughness (increasedenergy to break). Note that both core welded and shell welded substratescan display positive attributes such as faster drying, greater abrasionresistance, greater pilling resistance, more vibrant color, etc. whencompared to their raw substrate counterparts.

A picture of a piece of fabric constructed from approximately 50% raw(not processed) cotton yarn substrate and 50% moderately welded yarnsubstrate is shown in FIG. 9H, wherein the left portion of the figureshows the raw cotton yarn and the right portion of the figure showswelded cotton substrate. The split fabric underwent a pot dye processand reveals the enhanced, rich, and deeper, more vibrant color for theside of the fabric knitted from welded yarn substrate. The welded yarnsubstrate and resulting fabric has less hair at least because of theco-optimized process solvent application methods, viscous drag, andsolvent efficacy. Moreover, controlled volume reduction associated withthe welding, reconstitution, and drying steps of a welding process maybe configured to reduce the surface area and empty space within thewelded yarn substrate. This reduces the number of interfaces for whichlight can scatter. The net result of these combined effects is that thedye colorant(s) are more able to be seen through the welded substrate,which is more transparent than the raw substrate.

It should be noted that the relative lack of hair and reduction of emptyspace within fiber welded substrates is also responsible for thesurprising and dramatic reduction of time required to dry fiber weldedsubstrates. Again, the lack of hair at the substrate surface andreduction of empty space within the welded substrate by controlledvolume consolidation may be configured to limit the extent to which bulkwater can be integrated within the welded substrate. This is the reasonwhy welded substrates often dry greater than twice as fast (half as muchenergy required) as raw substrates. Lastly, it is observed that the samecoatings and surface modification chemistries that help reduce waterretention in raw cotton are even more effective with fiber welded cottonsubstrates. Similar results are also observed for silk, linen, and othernatural substrates.

Another process for producing a welded substrate may be configured touse a process solvent comprised of lithium hydroxide and urea forapplication to a substrate comprised of raw 30/1 ring spun cotton yarn.A perspective view of various apparatuses that may be configured toperform such a welding process is shown in FIG. 10A. The welding processand apparatuses therefor shown in FIG. 10A may be configured accordingto the various principles and concepts previously described hereinrelated to FIGS. 1, 2, & 6A-6F regarding viscous drag, process solventapplication, physical contact with process wetted substrate, etc. Inthis configuration, the substrate (e.g., yarn in the specificconfiguration shown in FIG. 10A) is dragged multiple times through agrooved tray, such as that shown in FIG. 6B. Each pass through the traycontributes additional process solvent to the substrate. The entirewelding path for the substrate may be contained within a temperaturecontrolled environment (in one configuration operating between −17° C.and −12° C.). The welded yarn substrate generally may reach an optimizedstrength after 14 minutes of low temperature welding time. After thisduration, the process wetted substrate may travel to a reconstitutionzone. For brevity, the aspects of this welding process related toprocess solvent recovery zone 4, solvent collection zone 7, solventrecycling 8, mixed gas collection 9, and mixed gas recycling zones 10are omitted.

A scanning electron microscope (SEM) image of a substrate that may beused with the welding process and apparatuses of FIG. 10A is shown inFIG. 10B, and an SEM image the resulting welded substrate is shown inFIG. 10E. Table 9.1 shows some of the key processing parameters used tomanufacture the welded substrate shown in FIG. 10E using the weldingprocess and apparatuses shown in FIG. 10A. The process parameters foreach column heading in Table 8.1 are the same as those previouslydescribed regarding Table 1.1. This welding process may be configured tomove multiple ends of yarn substrate simultaneously, and that virtuallyall important process parameters such as process solvent flow rate,temperature, substrate feed rate, substrate tension, etc. may beadjusted. In particular, this welding process and apparatuses may enablethe co-optimization of viscous drag and controlled volume consolidationfor particular welded substrates designed for specific products. Aselected number of welded yarn substrates are shown in FIGS. 10B-10F.

In other welding processes configured to use a process solvent comprisedof LiOH with urea, the mass ratio of process solvent to substrate may beless than the value shown in Table 9.1. For example, in one weldingprocess the ratio may be 0.5:1, and in another welding process it may be1:1, in another welding process it may be 2:1, in still another weldingprocess it may be 3:1 (which welding process and welded substratesproduced thereby are discussed in detail below regarding at least Table10.1), in another welding process it may be 4:1, and in yet anotherwelding process it may be 5:1. Furthermore, the ratio may be valuesother than integers, such as 4.5:1. Accordingly, the scope of thepresent disclosure is not limited by the specific value of this ratiounless so indicated in the following claims.

TABLE 9.1 Welding Solv. Pull Rate Zone Ratio Temperatures (° C.) (m/min)Time (sec) (g/g) Solvent Type Process solvent 30 m/min 135 >7 (to theLiOH:Urea application yarn 8:15 Wt % in zone/process saturation Sol'npressure temperature limit) zone: −14

Table 9.2 provides various attributes of a welded substrate producedusing the welding process and apparatuses of FIG. 10A using and the rawsubstrate shown in FIG. 10B using the parameters described in Table 9.1.The attributes were averaged as performed on approximately 20 uniquespecimens of welded yarn substrate, which attributes were collectedusing an Instron brand mechanical properties tester operating in tensiletesting mode approximating ASTM D2256. The mechanical property for eachcolumn heading in Table 9.2 are the same as those previously describedregarding Table 1.2. the stress (in grams) versus percent-elongationapplied to both a representative raw yarn substrate sample and arepresentative welded yarn substrate is shown in FIG. 10G, wherein thetop curve is the welded yarn substrate and the bottom trace is the raw.

TABLE 9.2 Norm. Breaking Breaking Strength Strength Elongation (g)(cN/dtex) (%) 417 2.07 1.9

A progression of the degree to which a substrate is welded is shown inFIGS. 10C-10E, all of which welded substrates may be manufactured usingthe process and apparatuses shown in FIG. 10A by varying the processparameters. The chemistry of the process solvent used for the processand apparatuses shown in FIG. 10A may be fundamentally different andimplicate various engineering consideration compared to the process andapparatus shown in FIG. 9A. That said, the overall welding process maybe operated according to similar principles and design concepts aspreviously described for the welding processes and associatedapparatuses shown FIGS. 7A, 8A, and 9A.

Moreover, the principles and concepts described regarding FIGS. 1 & 2are relevant to understand the overarching process design. In a mannersimilar to that as previously described regarding FIGS. 9C-9E, thewelding process and associated apparatuses shown in FIG. 10A may beconfigured such that the degree of welding is controllable. Aprogression of increased hair reduction and controlled volumeconsolidation of the cotton yarn substrate with various weldingparameters is shown from 10C to 10E. All of these welded substrates weremanufactured using a substrate comprised of raw 30/1 cotton yarn. TheSEM data show progressive elimination of loose hair on cotton yarns aswell as varying degrees of controlled volume consolidation for a lightlywelded substrate in FIG. 10C, moderately welded substrate in FIG. 10D,and highly welded substrate in FIG. 10E. Again, the absolute attributesof welded fabrics knitted or woven from welded substrates may vary, andmay be manipulated at least via the process parameters.

It is apparent that properly co-optimizing various process parameters(e.g., process solvent composition for efficacy and viscosity, byengineering the appropriate viscous drag, temperature, and time of theprocess zone, rate through the drying zone, etc.) that the weldingprocess can be controlled to achieve a similar effect as detailed inFIGS. 9C-9E. These data show some of the surprising effects that can beachieved by co-optimizing processes using the concepts of viscous dragand controlled volume consolidation. Stated another way, these data showthat co-optimized hardware, software, and chemistry can achieve desiredoutcomes and is the powerful new teaching demonstrated in this seminalwork.

An SEM image of a raw 2D substrate comprised of jersey knit cotton isshown in FIG. 12E, and a magnified image thereof is shown in FIG. 12G.An SEM image of the same fabric after it has been lightly welded isshown in FIG. 12F, and a magnified image thereof is shown in FIG. 12H.Table 10.1 shows some of the key processing parameters used tomanufacture the welded 2D substrate shown in FIGS. 12F & 12H. Thiswelding process may be configured such that virtually all importantprocess parameters such as process solvent flow rate, temperature,substrate feed rate, substrate tension, etc. may be adjusted. For thespecific example, the welding process was performed as a batch process,wherein process solvent was evenly applied to the raw substrate andallowed to act upon the substrate for seven minutes. Specific exampleshave been produced using greater or lower welding zone times withsimilar results, wherein a greater welding zone time generallycorresponds to a higher degree of welding, and a lower welding zone timegenerally corresponds to a lower degree of welding. Water was used as areconstitution solvent. During the process solvent application 2,process pressure/temperature zone 3, and process solvent recovery zone4, and drying zone 5 the substrate was constrained for controlled volumeconsolidation so that the individual yarns did not strongly adhere toone another. As a result, the welded 2D substrate retains a relativelysoft hand and the flexibility of the raw substrate, but exhibitssuperior burst strength (approximately 20% greater) and Martindale pilltest scores (increasing from 1.5 or 2 to at least 4) as compared to theraw substrate.

TABLE 10.1 Welding Zone Solv. Ratio Temperatures (C) Time (min) (g/g)Solvent Type Process solvent 7 3.0 LiOH:Urea application 8:15 Wt % inSol'n zone/process pressure temperature zone: −13

It is important to note that having multiple process solvent chemistriesgives a great amount of flexibility when adding functional materials andadditives to welded substrates, as well as configuring a specificwelding process to produce welded substrates exhibit the desiredattributes. Ionic liquid-based solvents (e.g., a welding process andapparatus as shown in FIG. 9A), for example tend to be slightly acidicespecially when the cation utilized is imidazolium-based. The alkalimetal urea-type process solvents (e.g., a welding process and apparatusas shown in FIG. 10A), on the other hand, are basic. Choice of processsolvent is often dictated based on the suitability of the processsolvent with a specific additive, and is an important new teaching tokeep in mind as functional materials are entrapped by fiber weldingprocesses as described in further detail below.

7. Functional Materials

As previously described, in an aspect of a welding process according tothe present disclosure, a substrate may be exposed to a process solventfor the purpose of subsequent physical or chemical manipulation of thesubstrate and/or properties thereof. The process solvent may at leastpartially interrupt intermolecular bonding of the substrate to open andmobilize (solvate) the substrate for modification. Although theforegoing illustrations and descriptions relate to functional materialincorporation via a welding process feature substrates comprised ofnatural fibers, the scope of the present disclosure is not so limitedunless indicated in the following claims.

As previously mentioned, one or more functional materials, chemicals,and/or components may be integrated within a welded substrate for 1D,2D, and 3D substrates and/or welded substrates. Generally, it iscontemplated that the incorporation of functional material may impartnew functionalities (e.g., magnetism, conductivity) without fulldenaturation of biopolymers that would otherwise be deleterious to theperformance characteristics (physical and chemical properties) of thesubstrate.

Generally, it is contemplated that the optimal integration of afunctional material(s) within a welded substrate may require optimizingthe viscous drag (which may be primarily associated with the processsolvent application zone 2 and/or process temperature/pressure zone 3)and/or adjusting volume controlled consolidation, both of which conceptsare described in detail above. For example, if it is desired for afunctional material to be evenly distributed across an entire surfacearea of a welded substrate, the viscous drag may be configured tofacilitate even distribution of a process solvent having a functionalmaterial disposed therein across the substrate. If it is desired for afunctional material to be concentrated at a specific location on thewelded substrate, the viscous drag may be configured to facilitateuneven distribution of such a process solvent. Accordingly, a weldingprocess configured to integrate functional materials into a weldedsubstrate may be optimized according to the concepts, examples, methods,and/or apparatuses as previously described above, and/or those describedin further detail below.

In an aspect of a welding process according to the present disclosure, asubstrate (which may be comprised of but is not limited to cellulose,chitin, chitosan, collagen, hemicellulose, lignin, silk, otherbiopolymer component that is held together by hydrogen bonding and/orcombinations thereof) may be swollen by an appropriate process solventcapable of disrupting intermolecular forces of the substrate, and inaddition, functional materials including but not limited to, carbonpowder, magnetic microparticles, and chemicals including dyes orcombinations thereof may be introduced either before, in conjunctionwith, or after the application of the process solvent(s). In an aspectof one welding process according to the present disclosure, fibrousbiopolymer substrates, functional materials, and the process solvent(which may be an ionic-based liquid or “organic electrolyte” but is notso limited unless indicated in the following claims) may be allowed tointeract under controlled temperature—which may include laser-based orother directed energy heating, as well as specific atmosphere andpressure conditions. After a prescribed amount of time, the processsolvent may be removed. Upon drying, the resulting functional materialmay be bonded to the substrate and may provide additional functionalproperties to the welded substrate compared to the properties of theoriginal substrate material.

The successful and permanent integration of functional materials intofibrous materials may be enabled by a welding process according to thepresent disclosure. Functional materials may be introduced with aprocess solvent and/or engaged with a substrate prior to the welding.Generally, in one aspect of a welding process natural fibers may belikened to an envelope into which functional materials may be placed,and once all or a portion of the empty space is removed during thewelding process, the functional material may trapped. For example, in anaspect of a welding process the welding process may be configured toembed a devices into the middle of a yarn, such as a micro RFID chip. Inanother process, the functional material is disposed in a material thatacts as a substrate binder. For example, a welding process may beconfigured such that fibers of the substrate may be coated with adissolved substrate binder during the welding process.

In one aspect of a welding process, a process solvent may be both activetowards the biopolymers in the natural substrate and also compatiblewith the functional material. In one aspect, functional materials mayinclude another biomaterial integrated with the substrate material—oneexample of such a configuration is using dissolved chitin as anantibacterial material in cellulose, or as a blood coagulant in a wounddressing. From the preceding it should be apparent that the scope of thepresent disclosure is not limited by the specific substrate, processsolvent, point in the welding process at which the functional materialis introduced, method and/or vehicle for introducing the functionalmaterial, how the functional material is retained in the weldedsubstrate, and/or type of functional material unless so indicated in thefollowing claims.

The depth of solvent and/or functionals material penetration of thesubstrate and the degree to which substrate fibers may be weldedtogether may be controlled at least by the amount of solvent,temperature, pressure, spacing of the fibers, form and/or particle sizeof functional material (e.g., molecules, polymers, RFID chip, etc.),residence time, other welding process steps, properties of substrate(e.g., moisture content and/or gradient) reconstitution method, and/orcombinations thereof. After a period of time, the process solvent may beremoved as previously discussed (e.g., with water, reconstitutionsolvent, etc.) to yield a welded substrate with incorporated (entrapped)functional materials, which may be retained via covalent bonding. Inaddition to polymer movement, chemical derivatization may also beundertaken during this process.

In one aspect of a welding process according to the present disclosure,the welding process may be configured to increase the material density(e.g., all or some of the open spaces between fibers may be removed) anddecreases the surface area of a finished welded substrate comprised of abundle of fibers compared to the material density and surface area ofthe substrate while simultaneously entrapping functional materialswithin the welded substrate. Generally, the degree to which the weldingprocess affects the amount of empty space within a given substrate maybe manipulated using at least the same variables as listed aboveregarding the depth of solvent and/or functional material penetration,which include but are not limited to the amount of solvent, temperature,pressure, spacing of the fibers, form and/or particle size of functionalmaterial (e.g., molecules, polymers, RFID chip, etc.), residence time,other welding process steps, properties of substrate (e.g., moisturecontent and/or gradient) reconstitution method, and/or combinationsthereof. In another aspect, the welding process may be configured tocontrol the specific region of a given substrate at which the emptyspace is being removed, which is described in further detail below.Again, functional materials may be added directly to the substrate(before welding), with the process solvent, and/or at any point in timebefore the process solvent is removed.

In one aspect of a welding process according to the present disclosure,the welding process may be configured to allow for spatial control ofthe alteration of the physical and chemical properties of the substrateusing concepts similar to those of multidimensional printing techniques.For example, by adding process solution to substrates with a devicesimilar to an inkjet printer or by heating selected portions of thesubstrate with directed energy beams (e.g., from an infrared laser orany other means known in the art) to activate welding in that selectedportion. Such welding processes are described in further detail belowrelated to FIGS. 11A-11E regarding modulated welding processes.

In one aspect of a welding process, the amount of process solvent withrespect to the amount of substrate may be kept relatively low to limitthe degree to which the substrate is modified during the weldingprocess. As previously described, the process solvent may be removedeither by a second solvent system (e.g., a reconstitution solvent), byevaporation if the process solvent is sufficiently volatile, or by anyother suitable method and/or apparatus without limitation unless soindicated in the following claims. A welding process may be configuredto increase the evaporation rate of the process solvent by placing theprocess wetted substrate under vacuum and/or subjecting it to heat.

A welding process may be configured to produce welded substrates thatmay constitute “natural fiber functional composites” or “fiber-matrixcomposites” that exhibit functionalities (e.g., physical and/or chemicalcharacteristics) not observed for the individual substrates and/orcomponents that make up the welded substrate if observed separatelyprior to the welding process.

A welding process may be configured to produce welded substratescomprised of fiber-matrix composites that contain functional materialsby utilizing a process solvent that is comprised of an ionicliquid-based solvent (“IL-based solvent”) as discussed in further detailbelow. One or more molecular additives in the process solvent may eitherincrease the efficacy of the process solvent as a swelling andmobilizing agent, and/or enhance the interaction of process solvent withone or more of the functional materials, and/or enhance the uptake ofthe process solvent and/or functional materials into natural fibersubstrates. IL-based process solvents are generally removed from weldedsubstrate (which may constitute a fiber-matrix composite) by areconstitution solvent, which generally involves rinsing/washing theprocess wetted substrate with a reconstitution solvent, whichreconstitution solvent may be comprised of excess molecular solvent(s).Upon drying, (which may be accomplished by subliming, evaporation,boiling away, or otherwise removing reconstitution solvent(s) or anyother suitable method and/or apparatus without limitation unless soindicated in the following claims) the welded substrate may constitute afiber-matrix composite that is finished and includes functionalmaterials with the associated novel physical and chemicalcharacteristics.

The substrate may be comprised of natural fibers, which natural fibersmay be comprised of cellulose, lignocellulose, proteins and/orcombinations thereof. The cellulose may be comprised of cotton, refinedcellulose (such as kraft pulp), microcrystalline cellulose, and thelike. In an aspect of a welding process, the welding process andapparatuses associated therewith may be configured for use with asubstrate comprised of cellulose in the form of cotton or combinationsthereof. Substrates comprised of lignocellulose may include bast fiberfrom flax, industrial hemp, and combinations thereof. Substratescomprises of proteins may include silk, keratin, and the like.Generally, the term “natural fibers” as it relates to substrates hereinis meant to include any high aspect ratio, fiber-containing naturalmaterials produced by living organisms and/or enzymes. Generallyspeaking, use of the term “fibers” indicates attention to themacroscopic (large scale) viewpoint of a material. Other examples ofnatural fibers include but are not limited to flax, silk, wool, and thelike. In one aspect of a welded substrate that may be produced accordingto the present disclosure, natural fibers generally may be thereinforcing fiber component of fiber-matrix composites. Additionally,natural fibers may be utilized in formats such as non-woven mats, yarns,and/or textiles.

While natural fibers typically are mainly composed of biopolymers, thereare biopolymer-containing materials that are not generally regarded asnatural fibers. For example, crab shells are mainly chitin, which is abiopolymer composed of N-acetylglucosamine monomers (a derivative ofglucose) but is not generally referred to as fibrous. Similarly,collagen and elastin are examples of protein biopolymers that providestructural support in many tissues that are not generally considered asfibrous.

The natural fibers that are produced by plants are generally mixtures ofdifferent biopolymers: cellulose, hemicellulose, and/or lignin.Cellulose and hemicellulose have monomer units that are sugars. Ligninhas phenol-based monomers that are cross-linked. Because ofcross-linking, lignin is generally not able to be solubilized (e.g.,swelled or mobilized) by IL-based solvents. Natural fibers that containsignificant amounts of lignin can, however, serve as structural supportfibers in composites. Additionally, natural fiber substrates thatcontain significant amounts of lignin may be swelled or mobilized usinga process solvent that is not IL-based.

The natural fibers that animals produce are often composed of protein(s)biopolymers. The monomer units in proteins are amino acids. There are,for example, many unique silk fibroin proteins that make up silks. Wool,horns, and feathers are composed primarily of structural proteinsclassified as keratin(s). The natural fibers may include cellulose,lignocellulose, proteins and/or combinations thereof. Generally,“natural fibers” may include but is not limited to unless so indicatedin the following claims cellulose, chitin, chitosan, collagen,hemicellulose, lignin, silk, and/or combinations thereof.

In an aspect of a welding process according to the present disclosure,the welding process may be configured to combine and convert a substratecomprised of natural fibers and functional materials into a weldedsubstrate that is a contiguous fiber-matrix composite. One purpose ofthe welding process may be to combine and convert a substrate comprisedof natural fibers and functional materials into a welded substrate thatconstitutes a natural fiber functional composite, herein also referredto as a “contiguous fiber-matrix composite” or simply “fiber-matrixcomposite.” Typically, functional materials are entrapped within thematrix portion of the fiber-matrix composite. A welding process may beconfigured such that natural fibers constitute the bulk of the fiberportion of welded substrate fiber-matrix composite and typically serveas the principle strengthening agent.

A. Ionic Liquid-Based Process Solvent Welding Processes

As previously discussed, a welding process may be configured to use aprocess solvent comprised of an ionic liquid. As used herein the term“ionic liquid” may be used to refer to a relatively pure ionic liquid(e.g., “pure process solvent” as defined herein above) and the term“ionic liquid-based solvent” (“IL-based solvent”) generally may refer toa liquid that is comprised both of anions and cations and may include amolecular (e.g., water, alcohols, acetonitrile, etc.) species and (thesolvent mixture) may be able to solubilize, mobilize, swell, and/orstabilize polymeric substrates. Ionic liquids are attractive solvents asthey are non-volatile, non-flammable, have a high thermal stability, arerelatively inexpensive to manufacture, are environmentally friendly, andcan be used to provide greater control and flexibility in the overallprocessing methodology.

U.S. Pat. No. 7,671,178, contains numerous examples of suitable ionicliquid solvents that may be used with various welding processesaccording to the present disclosure. In one welding process, the weldingprocess may be configured to use an ionic liquid solvent having amelting point less than about 200° C., 150° C. or 100° C. In one weldingprocess, the welding process may be configured for use with an ionicliquid solvent comprised of imidazolium-based cations with acetateand/or chloride anions. In another aspect of a welding process, theanions may include chaotropic anions including acetate, formate,chloride, bromide and the like alone, or in combinations thereof.

In another aspect of a welding process, the welding process may beconfigured for use with an IL-based solvent that may include polaraprotic solvents as a molecular additive, such as acetonitrile,tetrahydrofuran (THF), ethyl acetate (EtOAc), acetone, dimethylformamide(DMF), dimethyl sulfoxide (DMSO), and the like. More generally, themolecular additive for an IL-based process solvent system may be a polaraprotic solvent with a relatively low boiling point (e.g., less than 80°C. at ambient pressure) and relatively high vapor pressure. In anaspect, IL-based solvent may be about 0.25 mole to about four mol polaraprotic solvents per one mole of ionic liquid. In another aspect a polaraprotic solvent may be added to the IL-based solvent in ranges fromabout 0.25 mole to about two moles of total polar aprotic solvents per 1mole of ionic liquid. Polar protic solvents (e.g., water, methanol,ethanol, isopropanol) are typically present in ranges less than one moletotal polar protic solvents to one mole of IL-based solvents. In anotheraspect an IL-based solvent may include about 0.25 to about two moles ofa polar aprotic solvent for each mole of ionic liquid.

In an aspect of a welding process configured for use with an IL-basedsolvent as a process solvent, the amount of IL-based process solventadded may be about 0.25 parts to about four parts by mass of the processsolvent with one part by mass of the substrate.

In one aspect, a welding process may be configured to use an IL-basedsolvent comprised of one or more polar protic solvents, which polarprotic solvents include but are not limited to, water, methanol,ethanol, isopropanol and/or combinations thereof. In one aspect lessthan about one mole polar protic solvent may combined with up to aboutone mole of ionic liquid. A welding process may be configured to use anIL-based solvent comprised of one or more polar aprotic solvents (whichmay constitute a molecular additive to the process solvent system),which polar aprotic solvents include but are not limited to,acetonitrile, acetone, and ethyl acetate. Reasons for adding molecularadditives to an IL-based process solvent include adjusting the efficacyof the process solvent as a swelling and mobilizing agent, and/orenhancing the interaction of the process solvent with functionalmaterials, and/or enhancing the introduction of the process solvent andfunctional materials into the substrate(s). Such molecular additives mayinclude, but are not limited to, low boiling point solvents that canboth adjust efficacy of the IL as well as the rheology characteristicsof the process solvent. That is, the molecular additive and relativeamount thereof may be selected so as to result in at least the desiredviscous drag and controlled volume consolidation.

Generally, molecular components alone are non-solvents for most of thebiopolymer materials of interest. In one aspect of a welding process,the partial dissolution of biopolymers or synthetic polymer materialsmay be limited to instances in which there is an appropriateconcentration of about one mole of ionic liquid (ions) present for up toabout four moles maximum of molecular components. The molecularcomponent may either reduce the overall ability for ionic liquid ions tosolubilize, mobilize, and/or swell polymers in the substrate, or theymay increase the overall efficacy of the IL-based process solvent, whichmay depend at least upon the hydrogen bond donating and acceptingabilities of the molecular component(s).

Polymers present in biopolymer substrates as well as polymers in manysynthetic polymer substrates are generally held together and organizedat the molecular level by intermolecular and intramolecular hydrogenbonding. If molecular components decrease IL-based process solventefficacy, these molecular components can be useful to slow weldingprocesses and/or allow special spatial and temporal control nototherwise possible using pure ionic liquids. In one aspect of a weldingprocess, if the molecular component increases IL-based process solventefficacy, these molecular components can be useful to speed the weldingprocess and/or allow special spatial and temporal control not possibleusing pure ionic liquids. Additionally, in another aspect, molecularcomponents can significantly lower the overall cost of a weldingprocess, particularly the cost associated with the process solvent.Acetonitrile, for example, costs less than 3-ethyl-1-methylimidazoliumacetate. Thus, in addition to allowing manipulation of the weldingprocess for a given substrate, acetonitrile also may reduce the cost ofthe process solvent per unit volume (or mass) utilized.

When relatively large amounts of IL-based process solvents areintroduced to substrates comprised primarily of natural fibers (forreference “large” as used herein denotes roughly greater than 10 partsby mass process solvent to every 1 part by mass substrate) and withsufficient time and suitable temperature, the biopolymers within thesubstrate can be fully dissolved. In the present discussion, fulldissolution indicates disruption of the intermolecular forces (e.g.,disruption of hydrogen bonding due to the action of the solvent) and/orintramolecular forces that may be necessary to preserve naturalstructures, features, and/or characteristics within the substrate.Generally speaking, it is contemplated that for many welding processesaccording to the present disclosure, it will be advantageous toconfigure the welding process such that it does not involve fulldissolution of major amounts of biopolymers. In particular, fulldissolution often degrades natural fiber reinforcements by irreversiblydenaturing embodied natural biopolymer structure. However, in certainaspects of a welding process, such as when biopolymers are utilized asfunctional materials, it may be advantageous to fully dissolve thebiopolymer material. In a welding process so configured, the amount offully dissolved polymer (functional material) utilized may be typicallyless than 1% by mass relative to mass of IL-based process solventutilized. Given the relatively small amount of IL-based process solventthat is added to natural fibers, any fully dissolved biopolymermaterials may be minor components of the resulting welded substrate.

As native structure is lost, the natural material may lose its nativephysical and chemical properties. Accordingly, a welding process may beconfigured to limit the amount of IL-based process solvent addedrelative to a substrate comprising natural fiber. Limiting the amount ofprocess solvent introduced into the substrate may in turn limit theextent to which biopolymers are denatured from their natural structures,and thus may preserve the natural functionalities and/or characteristicsof the substrate, such as strength.

Surprisingly, a welding process according to the present disclosure mayfacilitate the creation of welded substrates comprised of functionalstructures, which may be produced via the controlled fusion/welding offibrous threads, woven materials, fibrous mats, and/or combinationsthereof with the addition of functional materials. The physical andchemical properties of the welded substrates may be reproduciblymanipulated by rigorous control of at least the amount of IL-basedprocess solvent applied, the duration of exposure to IL-based processsolvent, temperature, the temperature and pressure applied during thetreatment, and/or combinations thereof. One or more substrates and/orfunctional materials may be welded to create laminate structures withproper control of process variables. The surface of these substratesand/or functional materials may be preferentially modified while leavingsome of the substrate and/or functional material in the native state.Surface modifications may include but are not limited to manipulation ofthe material surface chemistry directly, or indirectly by theincorporation of additional functional materials to impart the desiredphysical or chemical properties. The functional materials may includebut are not limited to drug and dye molecules, nanomaterials, magneticmicroparticles, and the like that may be compatible with one or moresubstrates.

The functional material may be in suspension, dissolved or a combinationthereof in an IL-based solvent. The functional material may include butis not limited to conductive carbons, activated carbons, and the likewithout limitation unless so indicated in the following claims.Activated carbons may include but are not limited to chars, graphene,nanotubes, and the like without limitation unless so indicated in thefollowing claims. In one aspect, the welding process may be configuredfor use with a functional material that may include magnetic materialssuch as, NdFeB, SmCo, iron oxide, and the like without limitation unlessso indicated in the following claims.

In an aspect of a welding process disclosed herein, the welding processmay be configured for use with a functional material may comprised ofquantum dots and/or other nanomaterials. In another configuration of thewelding process the functional material may be comprised of mineralprecipitates, such as but not limited to clay. In yet anotherconfiguration of the welding process, the functional material mayinclude dyes, which dyes include but are not limited to UV-vis absorbingdyes, fluorescent dyes, phosphorescent dyes, and the like withoutlimitation unless so indicated in the following claims. In still anotherconfiguration of a welding process according to the present disclosure,the welding process may be configured for use with a functional materialcomprised of pharmaceuticals, selected synthetic polymers (e.g.,meta-aramid, which is also known as Nomex®), quantum dots, variousallotropes of carbon (e.g., nanotubes, activated carbon, graphene andgraphene-like materials), and may also include natural materials (e.g.,crab shells, horns, etc.) and derivatives of natural materials (e.g.,chitosan, microcrystalline cellulose, rubber), and/or combinationsthereof without limitation unless so indicated in the following claims.

In one aspect, a welding process may be configured for use with afunctional material comprised of a polymer. In such a configuration itis contemplated that it may be advantageous to select a polymer that isnot a crosslinking polymer to achieve the desired functional properties.However, the scope of the present disclosure is not so limited unlessindicated in the following claims. In one such configuration of awelding process the polymer may be comprised of a natural polymer orprotein such as cellulose starch, silk, keratin, and the like. In oneaspect of a welding process, polymer(s) constituting the functionalmaterial may be less than about 1% by mass of the IL-based processsolvent. Additionally, various natural materials may be utilized asfunctional materials.

As previously mentioned, a welding process may be configured such thatone or more functional materials are predispersed with the naturalfibers of a substrate, which substrates may be in the form of non-wovenmats and papers, yarns, woven textiles, etc. without limitation unlessso indicated in the following claims. Alternatively, functionalmaterials may be dissolved and/or suspended within IL-based processsolvents prior to application of the IL-based process solvent on thenatural fiber substrate. Upon swelling and mobilizing biopolymers in thenatural fiber substrate(s), functional materials may be entrapped withinthe matrix of the resulting welded substrate, which may constitute afiber-matrix composite.

The optimal values for the various process parameters will vary from onewelding process to the next, and depend at least upon the desiredcharacteristics of the welded substrate, the substrate chosen, theprocess solvent, the functional material, time the substrate is in theprocess solvent application zone 2 and/or process temperature/pressurezone 3, and/or combinations thereof. In one welding process it iscontemplated that an optimal temperature for the process solvent (andconsequently, a temperature for the process temperature/pressure zone 3)may be from about 0° C. to about 100° C.

A welding process may be configured so that the welding processcomprises combining IL-based process solvent with the substrate forabout one second to about one hour, or until the substrate is at least1.5% saturated, between 2% and 5% saturated, and at least 10% saturatedwith the IL-based process solvent. Such a welding process may beconfigured so that the functional material may be mixed with thesubstrate at the same time as the IL-based process solvent and thesubstrate or subsequent thereto.

After adequate exposure to the IL-based process solvent and functionalmaterial, a portion of the IL-based process solvent may be subsequentlyremoved from the process wetted substrate. In one aspect, the weldingprocess may be configured such that the portion of IL-based processsolvent is removed by rinsing with water, methanol, ethanol,isopropanol, acetonitrile, tetrahydrofuran (THF), ethyl acetate (EtOAc),acetone, dimethylformamide (DMF), or any other method and/or apparatussuitable for the particular welding process without limitation unless soindicated in the following claims.

In an aspect, a welding process may be configured such that it entrapsthe functional materials within a natural fibrous substrate by partiallydissolving either biopolymers or synthetic polymers with an IL-basedprocess solvent. In one configuration of a welding process, the weldingprocess may be configured for use with an IL-based process solvent thatcontains cations and anions and has a melting point below 150° C., andthe IL-based process solvent may include a molecular component aspreviously discussed. However, the scope of the present disclosure isnot so limited unless indicated in the following claims. The weldingprocess may be configured to form ionic bonds between the natural fibersof a substrate and the functional material.

In one aspect of a welding process configured according to the presentdisclosure, one or more functional materials may be incorporated intofibrous substrate prior to introduction of IL-based process solvent forpartial dissolution of the fibrous substrate. In another aspect, thefunctional materials may be dispersed within the IL-based solvent forpartial dissolution of fibrous substrate(s). In in another aspect one ormore functional materials may be dispersed within IL-based solvents. Instill another aspect of a welding process, the welding process may beconfigured to use heat to activate the partial dissolution of thenatural fiber substrate and/or the functional material(s). In anotheraspect of a welding process, the functional material(s) partiallydissolved may be biopolymers and/or synthetic polymers.

In one aspect of a welding process, the welding process may beconfigured to produce a natural fiber functional composite by using anatural fiber substrate, an IL-based solvent, and a functional material.First, the natural fiber substrate may be mixed with the IL-basedprocess solvent, and this mixing may continue until the natural fiber isappropriately swollen. Next, functional material may be added to theswollen natural fiber substrate and IL-based process solvent mixture. Inan aspect of a welding process, the welding process may be configured toapply a pressure and a temperature to the mixture for a period of time.Next, at least the pressure and removing at least a portion of theIL-based process solvent may result in a finished welded substrateconfigured as a natural fiber functional composite in one, two, or threedimensions.

In one aspect of a welding process, the welding process may beconfigured to use less than four parts by mass process solvent to everyone part by mass substrate, which mass ratio may be sufficient tointerrupt hydrogen bonding in only the outer sheath of natural fibers ofthe substrate. The degree to which hydrogen bonding is disrupted andnatural structures are denatured may be dependent at least upon processsolvent composition, as well as the time, temperature, and pressureconditions during which natural fiber substrates are exposed to IL-basedprocess solvents.

The extent to which swelling and mobilization of biopolymer occurs canbe qualitatively and, in some cases, quantitatively accessed at least byx-ray diffraction, infrared spectroscopy, confocal fluorescentmicroscopy, scanning electron microscopy, and other analytical methods.In one aspect of a welding process, the welding process may beconfigured to control certain variables to limit the amount of celluloseI to II conversion that occurs as described in further detail below atleast as related to FIGS. 15A & 15B. This conversion may be important inso far as it demonstrates the creation of fiber-matrix composites inwelded substrates, wherein natural fibers may retain some of theirnative structure and thus corresponding native chemical and physicalproperties. Swelling of substrate fibers is typically observed along awidth rather than a length, and in one aspect of a welding process thewelding process may be configured to increase the natural fiber diametermore than about 5%, 10%, or even 25%.

The mobilization of the outermost biopolymers in substrates comprised ofnatural fibers generally may be considered a characteristic of a weldingprocess according to the present disclosure. Mobilized polymer may beswollen such that functional materials can be inserted and entrappedwithin the resulting matrix of fiber-matrix composites in the weldedsubstrate. Because the primary mode of action of an IL-based processsolvent may be to swell and mobilize biopolymers by disruption ofhydrogen bonding, natural fiber substrates that contain relatively highamounts of lignin (roughly greater than 10% lignin) are not generallysuitable to swell and mobilize with IL-based process solvents. Theselignocellulosic natural fibers (e.g., wood fibers) can be incorporatedas relatively inert fiber reinforcement, however, lignocellulosic fiberscontaining roughly greater than 10% lignin do not provide much in theway of cellulose or hemicellulose matrix. This is at least in partbecause the cellulose and hemicellulose biopolymers that would otherwisebe swelled and mobilized by the IL-based process solvent are essentiallylocked within the cross-linked lignin biopolymer. As used herein, theterm “mobilized” includes an action wherein the functional materialmoves from the outer surface of substrate fibers to merge with that fromneighboring substrate fibers while material in the substrate fiber coreis left in the native state. Upon swelling and mobilizing biopolymersand entrapping functional materials, IL-based process solvents aregenerally removed from the fledgling fiber-matrix composite weldedsubstrate to be recycled.

As used herein, the term “reconstitution” is used to refer to theprocess by which process solvent(s) are rinsed/washed out of the processwetted substrate. This is typically accomplished by either flowingexcess molecular solvent (e.g., water, acetonitrile, methanol) aroundand through the process wetted substrate or by soaking the processwetted substrate in a bath(s) of molecular solvent. The choice ofreconstitution solvent depends on factors such as the type ofbiopolymers that compose the substrate as well as the composition forthe process solvent and ease by which the process solvent can berecovered and purified for reuse.

After removal of the process solvent, the reconstitution solvent istypically removed. This may be typically accomplished by any combinationof sublimation, evaporation, or boiling. Depending on the natural fibersubstrate, choice of functional materials, and whether the substrate isphysically constrained during all or a portion of the welding process,the substrate may undergo significant dimensional changes. For example,the diameter of yarns may be reduced by up to a factor of two as theempty space between individual natural fibers is consolidated to acontinuous fiber-matrix composite in the welded substrate.

In aspect of a welding process, the welding process may be configuredsuch that a portion of natural fibers in a substrate comprised ofnatural fibers is swollen about 2% to about 6% in diameter. Morespecifically, in an aspect of a welding process a portion of suchnatural fibers may be swollen more than about 3% in diameter.

In one aspect of a welding process, the mixture may be about 90% naturalfiber substrate and functional material and about 10% IL-based processsolvent by mas. Alternatively, the amount of IL-based process solventadded to the substrate and/or mixture of substrate and functionalmaterial may be about 0.25 parts to about four parts by mass of theprocess solvent with one part by mass of the natural fiber.

In an aspect of a welding process, the welding process may be configuredsuch that the pressure in the process temperature/pressure zone 3 may beabout a vacuum. Alternatively, the welding process may be configuredsuch that the pressure in the process temperature/pressure zone 3 isabout 1 atmosphere. In still another configuration, the pressure in theprocess temperature/pressure zone 3 may be between about one atmospheresto about ten atmospheres. As previously noted, the temperature and/ortime that the substrate is exposed to the process solvent may also becontrolled.

In one aspect of a welding process, the welding process may includeproviding a substrate comprised of a plurality of natural fibers,providing an IL-based process solvent, and providing at least onefunctional material. A welding process so configured may include mixingthe substrate IL-based process solvent and functional material in aprescribed sequence creating a chemical reaction that produces a weldedsubstrate constituting a natural fiber functional composite with thefunctional material penetrating the natural fibers and a plurality ofthe natural fibers and the functional material both may be covalentlybonded together. In one aspect of a welding process, at least thetemperature, pressure and time of the chemical reaction may becontrolled. A welding process may be configured to remove a portion ofthe process solvent, and it is contemplated that in certain applicationsit may be advantageous to remove a large portion of the process solvent,or substantially all of the process solvent.

In one aspect of a welding process, the welding process may beconfigured such that the prescribed process sequence introduces thefunctional material after the natural fiber substrate is mixed with theprocess solvent and the natural fiber substrate has achieved a swollenstate. In one aspect of such a welding process, the IL-based processsolvent may be diluted by a molecular solvent component, and wherein thepartial dissolution process of the biopolymers or synthetic polymermaterials commences after removal of the molecular solvent component(which removal may be accomplished by any suitable method and/orapparatus without limitation unless so indicated in the followingclaims, including but not limited to either evaporation ordistillation).

In one welding process, a carbon-cotton-process solvent mixture may beused to create a welded substrate having a thin-coat carbon/cotton bondthat, when exposed to cotton fabric in solution with the processsolvent, binds the carbon to the cotton fabric.

In one aspect of a welding process the process solvent and natural fibersubstrate may be blended to create surface tension characteristics thatallow the functional material (such as conductive carbon) to move intothe natural fiber substrate and/or form a thin coat of carbon functionalmaterial on the natural fiber substrate such as cotton. The examplesthat follow are illustrative of welded substrates and/or weldingprocesses for which functionalization is accomplished. The followingexamples are not meant to be read in a limiting sense, but rather asillustrative of the broader concepts and welding processes disclosedherein.

B. Functional Material Entrapment

The following illustrative examples details a welding process by whichone or more functional materials may be entrapped in a substratecomprised of a natural fibrous material, and in which and IL-basedprocess solvent may be introduced after the functional material has beenincorporated into the substrate. Again, the following examples are in noway limiting to the scope of the present disclosure unless so indicatedin the following claims. In one embodiment of the present inventionentrapment involves the incorporation of functional materials intofibrous substrates prior to introducing ionic liquid based solvents.

FIG. 3 illustrates a process for addition and physical entrapment ofsolid materials within a fiber-matrix composite with the sub-processesor components of FIG. 3 called-out as FIGS. 3A-3E. As depicted in FIG.3A, a natural fiber substrate 10 may include an amount of empty space.As shown in FIG. 3B, a disbursed functional material 20 may beincorporated into the natural fiber substrate 10. A point in time afterwhich an IL-based process solvent 30 has been introduced to the naturalfiber substrate 10 and functional material 20 (to create a processwetted substrate) is depicted in FIG. 3C. Controlled pressure,temperature, and time then may be used to create a swollen natural fibersubstrate 11 (as depicted in FIG. 3D) with the dispersed & bondedfunctional material 21.

In one aspect of a welding process, all or a portion of the IL-basedprocess solvent 30 then may be removed from the bonded functionalmaterial 21 and swollen natural fiber substrate 11 to yield weldedfibers 40 with entrapped functional material 22 while simultaneouslymaintaining a plurality of the natural fiber substrate 10 functionalcharacteristics and a plurality of the functional material 20 functionalcharacteristics. Unless otherwise noted, any attribute, features, and/orcharacteristic described herein for a welded fiber 40, 42 may extend toa fabric, textile, and/or other article comprised of the welded fiber40, 42.

In an aspect of a welding process, the welded fibers 40 may be acombination of covalently bonded functional material 21 and swollennatural fiber substrate 11. In an aspect of a welding process, thewelding process may be configured such that the resulting weldedsubstrate is comprised of cotton cloth functionalized with entrappedmagnetic (NdFeB) microparticles as observed via scanning electronmicroscopy data. In one aspect of a welding process, the welding processmay be configured for functional material 20 comprised of demagnetizedmicroparticles that may be incorporated as a dry powder into a naturalfiber substrate 10 comprised of cloth matrices. Surprisingly, thewelding process may entrap magnetic particles within the biopolymers ofthe natural fiber substrate 10 such that the magnetic particles areobserved to be strongly held within the welded fibers 40 and cannot beremoved even by aggressive laundering. In an aspect of a weldingprocess, the welding process may be configured such that similarprocedures to those described above have yielded similar advantagesand/or results in yarns and non-woven, fibrous mat natural fibersubstrates 10, including cotton and silk yarn matrices.

As discussed, the welding process described in the immediately precedingexamples may be configured such that suspensions of the nanomaterialfunctional materials 20 were added to biopolymer natural fibersubstrates 10 prior to exposure of either the functional material ornatural fiber substrate 10 to the IL-based process solvent. Differentmolecular solutions such as aqueous or organic (e.g., toluene) may beutilized alone or in conjunction with an IL-based process solvent 30depending at least on the surface chemistry of the functional material20, which may be comprised of quantum dots. The surface chemistry of thenanomaterial functional material 20 (i.e.,hydrophobicity/hydrophilicity) in conjunction with the natural fibersubstrate 10 may strongly impact the final location and dispersion ofnanomaterial functional material 20 within the resulting welded fibers40.

Surface chemistry may be used as a strategy for self-assembly of naturalfiber substrates 10 and functional materials 20 with an IL-based processsolvent to create microfabrication of functionality within compositematerials. For example, in one aspect of a welding process, quantum dotsmay be comprised of semiconducting materials that have size-dependentproperties. Their surfaces can be functionalized to be compatible withdifferent chemical environments for use in medicine, sensing, andinformation storage applications without limitation unless so indicatedin the following claims.

C. Functional Material Entrapment from Process Solvent/FunctionalMaterial Mixture

FIG. 4 illustrates a process for addition and physical entrapment ofsolid materials within a fiber-matrix composite with the sub-processesor components of FIG. 4 called-out as FIGS. 4A-4D utilizing materials(pre)dispersed in an IL-based solvent. A beginning natural fibersubstrate 10 with an IL-based process solvent 30 that has functionalmaterial 20 dispersed therein to make a process solvent/functionalmaterial mixture 32 is depicted in FIG. 4A. The functional material 20may be predisposed in the IL-based process solvent 30 to create theprocess solvent/functional material mixture 32 before the introductionof the natural fiber 12 as illustrated in FIG. 4A.

The natural fiber substrate 10 and process solvent/functional materialmixture 32 then may be combined as depicted in FIG. 4B (to create aprocess wetted substrate). At least controlled pressure, temperature,and/or time may be used to create a swollen natural fiber substrate 112within the process solvent/functional material mixture 32 as depicted inFIG. 4C. In an aspect of a welding process, the welding process may beconfigured such that all or a portion of the IL-based process solvent 30is then removed from swollen natural fiber substrate 112 to yield weldedfibers 42 with entrapped functional material 22 while simultaneouslymaintaining a plurality of the natural fiber substrate 10 functionalcharacteristics and a plurality of the functional material 20 functionalcharacteristics as depicted in FIG. 2D.

In an aspect of a welding process, the welded fibers 42 may be acombination of covalently bonded functional material 20 and swollennatural fiber substrate 112. In one aspect of a welding process, thewelding process may be configured such that the resulting weldedsubstrate is comprised of a functional material 20 comprised of amolecular dye entrapped within a natural fiber substrate 10 comprised ofcotton paper (fibrous mat), wherein the functional material 20 may bedispersed in an IL-based process solvent 30 (to create a processsolvent/functional material mixture 32) prior to application to thenatural fiber substrate 10. During a welding process, biopolymers(including, for example, cellulose in natural fiber substrate 10comprised of cotton paper) may be swollen such that the functionalmaterial 20 comprised of dye can physically diffuse into and becomeentrapped within the polymer matrix by covalent bonding. After thewelding process, the dye may remain visibly entrapped within the polymermatrix.

In one aspect of a welding process, the welding process may beconfigured such that certain information and/or chemical functionalitymay be controllably fused into natural fiber substrates 10 in theresulting welded fibers 40, 42. Such welded fibers 40, 42 may haveapplication at least to anti-counterfeiting features for paper-basedcurrency, dyeing (colorfast) of clothing, drug delivery devices, andother related technologies. In one aspect of a welding process, thewelding process may be configured for use with a functional material 20that may include molecular or ionic species able to be dispersed intoIL-based process solvents 30 for incorporation into the natural fibersubstrate 10.

Generally, the purpose of adding functional materials 20 may beapplication specific. For example, dyes with linkage chemistries thatcovalently bind with cellulose can be relatively expensive. In oneaspect of a welding process, the welding process may be configured toentrap lower-cost alternative dyes that do not have special linkagechemistry within the welded fibers 40, 42. Functional material 20comprised of one or more dyes that are entrapped within what was onceswollen and mobilized biopolymers (e.g., swollen natural fiber substrate11, 112) are not washed out as easily and may be applicable at least totextile and/or bar coding/information storage applications. In otheraspects, conductive functional materials 20 can be entrapped withinwelded fibers 40, 42 for energy storage applications. Entrapment offunctional materials 20 comprised of magnetic materials may be pertinentto textile-based actuators. The entrapment of functional materials 20comprised of pharmaceuticals and/or quantum dots may be relevant tomedical applications. The entrapment of functional materials 20comprised of clays is germane to enhanced fire retardancy. The additionof the biopolymer chitin as a functional material 20 may findapplication due to its known antibacterial properties. In short, thenumber of possible applications is extremely large. Functional materials20 include but are not limited to clays, all carbon allotropes, NdFeB,titanium dioxide, combinations thereof and the like as appropriate toaffect electronic, spectroscopic, thermal conductivity, magnetism,organic and/or inorganic materials having antibacterial and/orantimicrobial properties (e.g., chitin, chitosan, silver nanoparticles,etc.), and/or combinations thereof. Accordingly, the scope of thepresent disclosure is in no way limited to a specific functionalmaterial 20 and/or the specific application of the resulting weldedsubstrate and/or welded fibers 40, 42 unless so indicated in thefollowing claims.

In an aspect of a welding process, the welding process may be configuredsuch that no special covalent linkage chemistry is necessary to securelyentrap the functional material 20 of interest but rather the functionalmaterial 20 may be physically entrapped within the welded fiber 40, 42.In one aspect of a welding process, functional material 20 may beincorporated with high spatial control for encoding information orcreating color fast dyes, more generally, for integrating devicefunctionality. Multidimensional printing and fabrication techniquesenable the layering of many types of functionality within a singlematerial or object.

D. Functional Material Entrapment from Process Solvent/FunctionalMaterial/Polymer Mixture

As depicted in FIG. 5, with various sub-processes and components furthercalled out in FIGS. 5A-5D, in one aspect a welding process may beconfigured to incorporate functional materials 20 into a natural fibersubstrate 10 by introduction of the functional material 20 in a mixtureof IL-based process solvent and that also contains additionalsolubilized polymer.

As shown in FIG. 5A, such a process may begin with a natural fibersubstrate 10 and an IL-based process solvent 30 mixed with a functionalmaterial 20, such that the functional material 20 is dispersed in theIL-based process solvent 30 to constitute a process solvent/functionalmaterial mixture 32. A polymer 53 may be included in the processsolvent/functional material mixture 32 such that the polymer 53 isdissolved and/or suspended in the process solvent functional materialmixture 32. See also FIG. 5 illustrating a process for addition andphysical entrapment of solid materials within a fiber-matrix compositewith the sub-processes or components of FIG. 5 called-out as FIGS.5A-5D. The process solvent/functional material mixture 32 mixed with thepolymer 53 prior to application to the natural fiber substrate 10 isdepicted in FIG. 5A. The process solvent/functional material mixture 32having polymer 53 therein may then be introduced to the natural fibersubstrate 10 to create a process wetted substrate as depicted in FIG.5B. The welding process may be configured such that controlled pressure,temperature, and time are create a swollen natural fiber substrate 11,112 within the combined process solvent/functional material mixture 32,polymer 53, and natural fiber substrate 10 as depicted in FIG. 5C.

In one aspect of a welding process, all or a portion of the IL-basedprocess solvent 30 then may be removed from the process wetted substrate(which may be comprised of bonded functional material 21 and swollennatural fiber substrate 11, 112) to yield welded fibers 40 withentrapped functional material 22 and polymer 53 as shown in FIG. 5Dwhile simultaneously maintaining a plurality of the natural fibersubstrate 10 functional characteristics and a plurality of thefunctional material 20 functional characteristics.

In an aspect of a welding process, the welded fibers 40 may be acombination of covalently bonded functional material 21, polymer 53, andswollen natural fiber substrate 11. The polymer(s) may be comprised ofbiopolymers and/or synthetic polymers. In a welding process configuredfor use with certain polymers 53, additional polymers may act as both abinder (e.g., glue) as well as a rheological modifier to change solutionviscosity. Additionally, such a welding process may allow additionalspatial control over the final location of functional materials 20within welded substrate. In one aspect of a welding process, the weldingprocess may be configured for functional material 20 comprised of carbonmaterials and the natural fiber substrate 10 may be comprised of cottonyarn to yield a welded fiber 40, 42 that has been tested and verified assuitable for use as electrodes for high energy density supercapacitorsin woven fabrics. These may be adapted to provide flexible, wearableenergy storage devices.

A welding process may be configured to produce a welded fiber 40, 42with a functional material 20 comprised of one or more conductiveadditives such as organic materials (e.g., carbon nanotubes, graphene,etc.) or inorganic materials (silver nanoparticles, stainless steel,nickel, including fibers coated with metals and metal oxides, etc.).Such welded fibers 40, 42 may exhibit enhanced conductivitycharacteristics, and when combined with an appropriate electrolyte(e.g., either gel, polymer electrolytes, etc.), these welded fibers 40,42 (and/or fabrics and/or textiles produced therefrom) may be capable ofperforming electrochemical reactions and/or capacitive energy storage.

A welding process may be configured to produce a welded fiber 40, 42with a functional material 20 comprised of capacitive additives (e.g.,MnO2, etc.). Such welded fibers 40, 42 may exhibit enhanced energystorage characteristics when combined with an appropriate electrolyteincluding either gel or polymer 20 electrolytes.

A welding process may be configured to produce a welded fiber 40, 42with a functional material 20 comprised of photoactive additives (e.g.,TiO2, etc.). Such welded fibers 40, 42 may exhibit enhancedself-cleaning (e.g., in the case of a wide bandgap semiconductor such asTi02) and/or ultra violet light resistance characteristics.

Other applications for welded fibers 40, 42 produced according to awelding process according to the present disclosure may include but arenot limited to technologies ranging from anti-counterfeiting to drugdelivery applications. Furthermore, the preceding list of functionalmaterials is not meant to be exhaustive and/or limiting, and otherfunctional materials may be used without limitation unless so indicatedin the following claims.

8. Modulated Welding Processes

As previously described herein above, a welding process may beconfigured to allow for a wide variety of welded substrate finishes(e.g., yarn finishes) to be produced from conventional substrates(non-fiber welded), which substrates may be comprised of yarn and/ortextile substrates in certain configurations of a welding process. Forexample, a welding process may be configured as a modulated weldingprocess via the use of a process solvent that is pumped with acontrolled, variable and/or modulated rate and/or by moving thesubstrate (e.g., yarn, thread, fabric, and/or textile) through thewelding process at a variable rate and/or by varying the process solventcomposition, and/or by varying the temperature and/or pressure in theprocess solvent application zone 2, process temperature/pressure zone 3,process solvent recovery zone 4, by varying tension (e.g., of thesubstrate, process wetted substrate, etc.), and/or combinations thereof.

In one aspect a welding process may be configured to allow for specificand precise control of the ratio of process solvent relative to asubstrate comprised of fibers such that the welding process may converta controllable amount of the fiber within the substrate to a weldedstate. The ratio of process solvent relative to substrate may beoptimized at least depending on the particular process solvent andcharacteristics of the substrate. For example, in a welding processconfigured to use process solvent mixtures such as an ionic liquids(e.g., 3-ethyl-1-methylimidizolium acetate, 3-butyl-1-methylimidizoliumchloride, etc.) mixed with a polar aprotic additive (e.g., acetonitrile)might utilize a process solvent ratio ranging from one part by massprocess solvent added to one part by mass substrate to four parts bymass process solvent added to one part by mass substrate. Another aspectof a welding process may employ a process solvent that is comprised of acold alkaline (sodium hydroxide and/or lithium hydroxide) with ureasolution having process solvent ratios ranging from two parts by massprocess solvent to one part by mass substrate to more than ten parts bymass process solvent to one part by mass substrate. Table 11.1 givesprocess parameter examples that have been used successfully forfabricating welded yarn utilizing welding systems with a process solventcomprised of both an ionic liquid and with a process solvent comprisedof an aqueous hydroxide solution. The parameters shown in Table 11, butwhich parameters are not limiting to the scope of the present disclosureunless so indicated in the following claims.

In one welding process utilizing a process solvent comprising ahydroxide and urea in aqueous solution, the hydroxide may be comprisedof NaOH and/or LiOH. In a welding process, the hydroxide may becomprised of LiOH at between 4 and 15 weight percent and urea at between8 and 30 percent. In certain applications it may be advantageous toconfigure the process solvent such that it is comprised of LiOH atbetween 6 and 12 weight percent and urea at between 10 and 25 percent.In still another application it may be advantageous to configure theprocess solvent such that it is comprised of LiOH at between 8 and 10weight percent and urea at between 12 and 16 percent.

TABLE 11.1 Process Solvent To Welding Substrate Ratio Process Time forReconstitution (wt solvent:wt Process Solvent Temperature yarn (s)Solvent substrate) EMIm OAc 50° C.-100° C. 5-15 water, acetonitrile,0.5-6 or other aprotic solvent 1 mol EMIm OAc + 50° C.-100° C. 5-15water, acetonitrile, 0.75-6  2 mol ACN or other aprotic solvent 1 molEMIm OAc + 50° C.-100° C. 10-25  water, acetonitrile,   1-6 4 mol ACN orother aprotic solvent BMIm Cl 90° C.-130° C. 5-30 Water, acetonitrile,0.5-6 or other aprotic solvent 1 mol BMIm Cl + 80° C.-130° C. 5-45Water, acetonitrile, 0.75-6  1 mol ACN or other aprotic solvent NaOH orLiOH −18° (freezing 60-300 water   2-10 (~7 wt %) + urea pt) - −10° C.(~12 wt %) aqueous solution

With regard to the temperature ranges specified in Table 11.1, note thattemperature may be optimized for the specific composition of the processsolvent system. Moreover, the temperature and composition of the processsolvent system may be co-optimized together at least with the solventapplication zone 2 hardware and/or process control software and/orapparatuses in order to achieve the desired amount and location ofwelding on the substrate. That is, fiber welding that either providesconsistent welded substrate attributes or modulated substrateattributes. This may also be achieved by applying viscous drag wereappropriate during solvent application as well as the processtemperature/pressure zone 3.

As shown in Table 11.1 and described herein above, a process solventsystem may be configured as a mixture of an IL liquid and a molecularadditive. The mole ratio of IL liquid to molecular additive may varyfrom one welding process to the next, and may affect the optimaltemperature of the process solvent system during application thereof tothe substrate. For example, in a welding process configured to utilize aprocess solvent system comprised of 1 mol BMIm Cl to 1 mol ACN, thevapor pressure of ACN may result in difficult processing conditions tocontrol (related to health and safety) if the temperature is raisedabove 120° C. (which is where the rate of welding may be optimal). As aresult of this constraint, the welding temperature is set to a lowertemperature (e.g., 105° C.) but then requires a longer duration (>30seconds) at such temperature. By contrast, in a welding processconfigured to utilize a process solvent system comprised of EMIm OAc,the optimal temperature may be between 80° C. and 100° C. because theeffectivity of the process solvent is higher than BMIm Cl and thus thewelding time with EMIm OAc in this temperature range can be 5-15seconds. Accordingly, the optimal temperature for at least the processsolvent application zone 2, process temperature/pressure zone 3, andother steps of a welding process may vary from one application thereofto the next, and is therefore in no way limiting to the scope of thepresent disclosure unless so indicated in the following claims.

Referring now to Tables 9.1, 10.1, and 11.1 (all of which provide keyprocess parameters for a welding process configured to use a processsolvent comprised of an aqueous hydroxide), the optimal ratio of processsolvent to substrate (on a mass or weight basis) may vary at least basedon the substrate format type. For example, a welding process configuredfor use with a 2D substrate may have a ratio of 0.5 to 7, and somewelding processes may be optimally configured at a ratio ofapproximately 3.7. A welding process configured for use with a 1Dsubstrate may have a ratio of 4 to 17, and some welding processes may beoptimally configured at a ratio of approximately 10. It has beenobserved that a ratio of approximately 10 or higher, and specifically aratio of 17, results in a condition in which the process wettedsubstrate is beyond saturation with respect to the process solvent, suchthat excess solvent is present at the exterior of the process wettedsubstrate that is not absorbed by the substrate and/or process wettedsubstrate. However, the specific ratio for a welding process utilizingan IL-based process solvent or an aqueous hydroxide process solvent inno way limit the scope of the present disclosure unless so indicated inthe following claims.

TABLE 11.2 Process Solvent To Welding Substrate Ratio Process Time forReconstitution (wt solvent:wt Process Solvent Temperature yarn (s)Solvent substrate) 1 mol EMIm OAc + 50° C.-100° C. 5-15 water,acetonitrile, 0.75-6 2 mol ACN + or other aprotic 1% (by wt.) solventCellulose Additive BMIm Cl + 90° C.-130° C. 5-30 Water, acetonitrile, 0.5-6 0.5% (by wt.) or other aprotic Cellulose Additive solvent

With regard to the values and compositions of process solvents shown inTable 11.2, note that the addition functional material additives allowsfor spatial modulation of welding and unique controlled volumeconsolidation. The addition of functional materials such as dissolvedcellulose with the appropriate hardware and controls in the weldingprocess may allows for the surprising effect of a shell welded yarn aspreviously described in detail above at least related to FIGS. 9I & 9J.That is, the amount of welding may be controlled through the substratecross section (i.e., the yarn diameter in the specific examples of FIGS.9I & 9J) and may create a welded substrate (i.e., welded yarn substratesin the specific example) that exhibit both improved toughness andelongation as compared to raw substrate control samples.

Note as well that the type of reconstitution solvent and temperaturethereof in conjunction with the different values described in Table 11.1can also yield surprising effects on the controlled volume consolidationas the reconstituted wetted substrate is dried. An SEM image of a raw 1Dsubstrate comprised of 18/1 ring spun cotton yarn is shown in FIG. 13.One welded substrate is shown in FIG. 14A and another is shown in FIG.14B, both of which were produced from the raw substrate shown in FIG.13. The welded substrates shown in both FIGS. 14A & 14B were producedusing the welding process and apparatuses shown in FIG. 9A.

TABLE 12.1 Norm. Breaking Breaking Strength Strength Elongation (g)(cN/dtex) (%) 453 1.38 5.7

Table 12.1 provides various attributes of the raw substrate shown inFIG. 13. The attributes were averaged as performed on approximately 20unique specimens of welded yarn substrate, which attributes werecollected using an Instron brand mechanical properties tester operatingin tensile testing mode approximating ASTM D2256. The mechanicalproperty for each column heading in Table 12.1 are the same as thosepreviously described regarding Table 1.2.

Table 13.1 shows some of the key processing parameters used tomanufacture both the welded substrate shown in FIG. 14A and that shownin FIG. 14B. The process parameters for each column heading in Table13.1 are the same as those previously described regarding Table 1.1.

TABLE 13.1 Welding Solv. Pull Rate Zone Time Ratio Temperatures (° C.)(m/min) (sec) (g/g) Solvent Type Process solvent 18.0 8.5 2.0 EMImOAc:ACN application zone: 90 1:2 (Mole Ratio) process pressuretemperature zone: 90

Table 13.2 provides various attributes of the welded substrate shown inFIG. 14A produced using the parameters described in Table 13.1. Theattributes were averaged as performed on approximately 20 uniquespecimens of welded yarn substrate, which attributes were collectedusing an Instron brand mechanical properties tester operating in tensiletesting mode approximating ASTM D2256. The mechanical property for eachcolumn heading in Table 13.2 are the same as those previously describedregarding Table 1.2.

TABLE 13.2 Norm. Breaking Breaking Strength Strength Elongation (g)(cN/dtex) (%) 556 1.69 2.4

Table 13.3 provides various attributes of the welded substrate shown inFIG. 14B produced using the parameters described in Table 13.1. Theattributes were averaged as performed on approximately 20 uniquespecimens of welded yarn substrate, which attributes were collectedusing an Instron brand mechanical properties tester operating in tensiletesting mode approximating ASTM D2256. The mechanical property for eachcolumn heading in Table 13.3 are the same as those previously describedregarding Table 1.2.

TABLE 13.3 Norm. Breaking Breaking Strength Strength Elongation (g)(cN/dtex) (%) 521 1.58 2.4

In contrasting FIG. 14A with FIG. 14B, it is apparent how volumecontrolled consolidation may be manipulated to yield certain attributesof the welded yarn substrate. Specifically, a contrast of FIGS. 14A &14B shows how the method, composition of reconstitution solvent, and/orconfiguration of the process solvent recovery zone 4 (and/or other stepof a welding process) may impact the controlled volume consolidation ofthe welded yarn substrate, and, consequently, the mechanical propertiesand/or other important attributes of the welded substrate. One suchattribute is the “hand” of the yarn (i.e., the way it feels to aperson's touch) and resulting fabrics made therefrom.

Specifically, both the welded yarn substrate shown in FIG. 14A and thatshown in FIG. 14B were produced using a welding process wherein thereconstitution solvent was comprised of water. However, for the weldedyarn substrate of FIG. 14A the temperature of the water was 22° C. andfor that in FIG. 14B it was 40° C. As is apparent from a contrast ofFIGS. 14A & 14B, the welding process used to produce the weldedsubstrate shown in FIG. 14A (colder reconstitution solvent) results in awelded substrate with significantly softer hand compared to the weldedsubstrate shown in FIG. 14B (warmer reconstitution solvent). Fabricsmade from welded yarn substrates that have been produced with a weldingprocess having a reconstitution solvent above 40° C. can havesignificantly different hand characteristics than fabrics made fromsimilar welded yarn substrates produced with a welding process having areconstitution solvent at room temperature. The configuration of theprocess solvent recovery zone 4 (e.g., reconstitution method) andconditions thereof is thus an important new parameter.

Still referring to FIGS. 14A & 14B, which were produced from identicalwelding processes but for the temperature of the reconstitution solvent,it is apparent that the temperature of the reconstitution plays animportant role in the controlled volume consolidation of the welded yarnsubstrate. Again, some mechanical properties of the welded yarnsubstrate of FIGS. 14A & 14B are shown in Table 13.2 and 13.3,respectively. Whereas both welded yarn substrates show significantimprovement in the mechanical properties over the raw yarn substrate(e.g., a 15-23% improvement over the raw yarn substrate), the weldedyarn substrate shown in FIG. 14B (see also Table 13.3) that wassubjected to a reconstitution solvent at elevated temperature has aslightly larger diameter and more loose fiber/hair at its surface.Although the welded yarn substrates in FIG. 14B are slightly morefibrous than those shown in FIG. 14A, the amount of fiber in FIG. 14B isfound to be less than that amount for a corresponding raw yarn substrateshown in FIG. 13. Moreover, the fiber on the welded yarn substrate inFIG. 14B is anchored to the welded yarn substrate in such a way as toresist separating from the welded yarn substrate away as lint. Modifiedfiber/hair structure at or near the surface of a welded yarn substratethrough a welding process may be an important attribute that effects thehand of fabrics knitted or woven from welded yarn substrates.

Generally, particular values of the solvent ratios within the rangesmentioned in the immediately above can be utilized produce veryconsistent welded yarn for substrates comprised of yarn when the ratiosare not varied, but rather held constant and so long as other criticalvariables such as temperature are also held constant during the weldingprocess. In so doing the welding process may be configured to yield awelded substrate that exhibits a consistent amount of welding such thatwelded yarns may have a consistent amount of welded fiber along thelength of the welded yarn.

Appropriate control of the dynamic process solvent ratio (herein definedas the ratio of the mass of process solvent relative to the mass of thesubstrate), the composition of the process solvent, the pressure andmethod by which the process solvent is applied yields novel effects. Forexample, proper dynamic control may be used in a welding process toyield a welded substrate with heather and/or space dye (multi-coloredeffect) appearance in which a welded substrate comprised of a yarn ortextile may have a variable degree of coloration that may be due to thedynamic control of the welding process. Creating a heather and/or spacedye effect may only be revealed upon dyeing and finishing if thesetextile manufacturing steps are accomplished after the welding process.

However, a modulated welding process is not limited to producing heatheror space dye effects but also may be configured to produce “embossed”yarns having a variable diameter (with changing yarn weight, which is tosay without needing a substrate of variable length and/or diameter) andany number of other unique effects that for which there do not yet existtextile industry terminologies to describe. The degree to which theeffect is observed may also be a function of the yarn or textilesubstrate that is acted upon. For example, the type of spinning process(e.g., ring spinning, open end spinning, vortex spinning, etc.) that wasutilized to produce a substrate comprised of a yarn may requiresdifferent welding conditions (e.g., different process solvent ratiosand/or application methods) from one another.

A. Comparison of Modulated and Non-Modulated Welding Processes

One illustrative example of a modulated welding process will now bedescribed and compared to a non-modulated welding process (such aspreviously described herein above). However, the foregoing illustrationis not meant to be limiting in any manner, and accordingly the specificparameters thereof do not limit the scope of the present disclosureunless so indicated in the following claims.

In a non-modulated welding process, the welding process may beconfigured for a substrate comprised of 30/1 ring spun yarn, whichsubstrate may be converted into an extremely consistent welded substratewith consistent coloration, consistent fell and finish, and consistentamount of visible exterior fiber ‘hair’ by operating the welding processconsistently. For example, by configuring the welding process to utilizea stable process solvent to substrate mass ratio, steady yarn movementrate through the welding process, consistent temperature and pressure,etc. This welded substrate may also exhibit all of some of the weldedsubstrate attributes previously described herein above.

Alternatively, if desired, a modulated welding process may be configuredfor a substrate comprised of 30/1 ring spun yarn to convert thesubstrate into a welded substrate comprised of a yarn that has amulti-colored heather or space dye appearance by dynamically varyingcertain parameters of the modulated welding process. This is asurprising and very useful result because the welding process can beautomated to convert a substrate comprised of commodity ring spun 30/1yarn (which is a generally uniform product produced at large scale) intoa welded substrate comprised of welded yarn having a unique look, feel,and/or finish for a multitude of end uses and applications. Incorrelative modulated welding processes, the welding process may beconfigured for use with substrates comprised of heavier (including butnot limited to Ne 18 yarn) and lighter (including but not limited to Ne40 yarn) commodity and specialized yarns without limitation unless soindicated in the following claims.

Moreover, a modulated welding process is not limited to configurationsthereof for creating specialized effects and finishes just withsubstrates comprised of yarns. For example, application of processsolvents including but not limited to mixed inorganic solvents such asaqueous solutions of lithium and/or sodium hydroxide with urea can beapplied to both substrates comprised of yarns and even to substratescomprised of an entire textile that has itself been produced from eitherconventional material (e.g., yarn that has not been through a weldingprocesses) or welded substrates (e.g., welded yarn).

Treatment of fabrics using a welding process can be accomplished over alocalized region or regions of a fabric or garment. For example,processes such as those used in inkjet and/or screen printing of processsolvent can be a very useful method by which to accomplish area-specificwelding processes for 2D and/or 3D substrates. Alternatively, a weldingprocess may be configured to yield a 2D and/or 3D welded substrate ofrelative uniform characteristics over an entire piece of material orgarment.

When a welding process is configured and employed with appropriatecontrol of various parameters thereof (e.g., limited welding time,relatively low process solvent ratio, etc.), the welding process mayyield welded substrates with improved strength and pillingcharacteristics of woven and knitted textiles compared to theirconventional raw substrate counterparts without excessive welding ofyarn junctions within textiles. Alternatively, a welding processdifferently configured (e.g., longer welding time, higher processsolvent ratios, etc.), may yield a welded substrate comprised of a wovenor knitted material with welded and/or partially welded yarn junctionsin woven and knitted materials to provide much stiffer and/or morerobust materials. An advantage of employing a welding process on a 2Dand/or 3D substrate (e.g., fabric, textiles) compared to 1D substrates(e.g., yarn, thread) is that large amounts of materials be treatedsimultaneously. However, as previously described above, weldingsubstrates comprised of yarn and/or thread prior to weaving and/orknitting may yield a number of manufacturing and performance synergies.The choice of when and how to apply a given welding process to aparticular substrate is largely dependent on the type of intendedoutcome/end use application for the welded substrate, and is thereforein no way limiting to the scope of the present disclosure unless soindicated in the following claims.

In addition to the possibilities listed above, it is possible toconfigure a welding process to form the cross section of 1D (e.g., yarnand/or thread), 2D, and/or 3D substrates (e.g., fabric and/or textilesas applicable to either 2D and/or 3D substrates) and/or the componentsof the substrates (e.g., an individual yarn or thread of a 2D and/or 3Dsubstrate) into shapes other than circular shapes or welded substrateshaving circular cross-sectional shapes. Possible shapes include but arenot limited to flattened oval or ribbon-like shapes. This may beaccomplished by configuring a welding process to utilize appropriatelyshaped dies and/or rollers positioned within the process solventapplication zone 2, process temperature/pressure zone 3, process solventrecovery zone 4, drying zone 5, and/or combinations thereof.

Conventional yarns used as substrates normally yield welded substratesthat exhibit cross-sectional shapes that are roughly circular after thewelding process. Generally, this may be because potential energy may beminimized as capillary forces draw process solvent(s) toward the core ofa yarn as fibers are welded/fused. A welding process may be configuredto yield welded yarn substrates that have non-circular cross-sectionalshapes by employing at least specific forming methods and/or apparatusesto manipulate the process wetted substrate and/or forming thereconstituted wetted substrate as it dries.

B. Modulated and Non-Modulated Welding Processes Using SpatiallyControlled Heating and/or Spatially Controlled Process SolventApplication

Spatial control of adding chemicals to substrates (e.g., inkjet printingof ionic liquids) has been previously disclosed, such as in U.S. Pat.No. 6,048,388. The spatial control of a welding process may also bedirectly controlled at least by heat activation in selected regionswithin the substrate (to manipulate any characteristic and/or attributeof the resulting welded substrate as described in detail above), whereina welding process may be configured as a modulated welding process usingspatially controlled heating. IL-based solvents typically do notappreciably weld (modify) natural fiber substrates 10 at roomtemperature (about 20° C.) for time frames on the order of minutes.Typically, it may be advantageous to apply heat to activate and/or speedthe welding process. This may involve heating the entire substrate totemperatures greater than about 40° C. for at least several seconds.

A schematic representation of a welding process that may be configuredas a modulated welding process is shown in FIG. 11A, which may utilize2D substrates. The modulated welding process shown in FIG. 11A may beconfigured to use a beam of infrared (laser) light to heat specificlocations of a substrate to which process solvent has been previouslyapplied. Heat from the directed energy beam may activate the weldingprocess in specific locations of the substrate and is evident in oneconfiguration of a welding process by the conversion of cellulose I (fornatural cotton substrate) to cellulose II (cotton substrate afterwelding) and controlled volume consolidation (i.e., the thickness of thesubstrate may be reduced while the area is unaffected).

As is evident by a comparison of FIGS. 10B and 11E, changes to thesurface of the substrate are evident via visual inspection, whichchanges are a result of exposure from a directed energy source.Additionally, by controlling the power of the energy source (keeping thepower sufficiently low), the substrate (cellulose in this example) wasnot ablated. A welding process may be configured to utilize any suitablewavelength of electromagnetic energy without limitation unless soindicated in the following claims including but not limited to visiblelight, microwaves, ultra violet light, and/or combinations thereof toachieve spatially controlled heating.

Referring now to both FIGS. 11A & 11B, which provide schematicrepresentations of modulated welding processes applied to 2D substrates,FIG. 11A depicts spatially controlled heating and FIG. 11B depictsspatially controlled process solvent application. Again, FIG. 11Adepicts the addition of heat to a substrate, process wetted substrate,and/or process solvent by a directed energy beam. The process solventamount and/or composition may be modulated at specific locations orbroadcast over the entire substrate. Referring to FIG. 11B, the amountof process solvent and/or composition thereof may be modulated atspecific locations, and then large areas of the process wetted substratemay be heated by a broadcast energy source. Both modulated weldingprocesses may result in volume controlled consolidation of the substrateafter reconstitution and drying.

Referring now to both FIGS. 11C & 11D, which provide schematicrepresentations of modulated welding processes applied to 1D substrates,FIG. 11C depicts spatially controlled heating and FIG. 11D depictsspatially controlled process solvent application. As shown in FIG. 11A,heat may be added to a substrate, process wetted substrate, and/orprocess solvent via a pulsed energy source. The process solvent amountand/or composition may be modulated at specific locations or broadcastover the entire substrate. Referring to FIG. 11D, the amount of processsolvent and/or composition thereof may be modulated at specificlocations, and then large areas of the process wetted substrate may beheated by a broadcast energy source and/or by a pulsed energy source.Both welding process may be configured to provide careful control overprocess solvent efficacy and rheology, and associated viscous drag inorder to achieve the desired effect.

An image of a modulated welded yarn substrate that was produced via amodulated welding process wherein the flow rate of the process solventwas modulated (e.g., pulsed in a manner similar to that depicted in FIG.11D) is shown in FIG. 11E. Configuring the modulated welding process toachieve the desired viscous drag (which in this example was done byphysical contact with the process wetted substrate to spread the processsolvent from the initial point of contact) resulted in alternatingportions along the length of the welded substrate that were lightlywelded and highly welded. In FIG. 11E, the portion on the right side ofthe figure is lightly welded and the portion on the right side of thefigure is highly welded.

An image of a fabric made from a welded substrate that has be subjectedto a modulated welding process is shown in FIG. 11F. The weldedsubstrate used to produce the fabric in FIG. 11F may be produced via thewelding process and apparatuses shown in FIG. 9A and previouslydescribed herein. The modulated welding process was achieved viamodulating process solvent pumping rate and viscous drag. By propercontrol of the welding process, a variable degree of controlled volumeconsolidation and specific degree of welding was achieved. The neteffect was to modulate the amount of hair and empty space in the weldedyarn substrate.

After this modulated welded yarn substrate was knit into a fabric anddyed, the depth of color was found to vary with the degree of welding.This yielded the surprising ‘space dye’ or ‘heather’ effect evident fromFIG. 11F. Typically, in the fashion industry, this effect requiresmultiple yarns to be knitted into a single fabric. Modulated fiberwelding not only provides the aforementioned benefits of quicker dryingtimes and enhanced moisture management, but in this case, also adds aunique yet controllable color modulation that is of interest for avariety of fashion applications. Combining the modulated welding effectwith a predetermined stitch length and/or with the tightness factor of aweave gives even further enhancement over the fabric color and texture.This is new result may find use in any number of conventional andfunctional products.

As briefly mentioned above, a welding process may be configured tocontrol the amount of cellulose I crystal that is converted to celluloseII crystal. Referring now to FIG. 15A, a graphical representation ofx-ray diffraction data (XRD) for a raw cotton yarn substrate (plot A)and a cotton yarn that was fully dissolved with excess ionic liquidprocess solvent and then reconstituted (plot B) is shown therein. Asused herein, plot B does not represent a “welded substrate” or “weldedyarn substrate” or any other substrate produced according to the presentdisclosure because the entire raw yarn substrate was denatured and thenative biopolymer structure was completely changed unless otherwiseindicated in the following claims. In plot A, native cotton cellulosepolymer is clearly shown in the cellulose I state. In plot B, there isclearly less crystalline character of cellulose II, which is present incotton that has been fully dissolved and had its native structure whollydisrupted.

Table 14.1 shows some of the key processing parameters used tomanufacture three separate welded substrates, wherein the processingparameters for the first two rows may be employed with the weldingprocess and apparatuses shown in FIG. 9A, and wherein the processingparameters for the third row may be employed with the welding processand apparatuses shown in FIG. 10A. The process parameters for eachcolumn heading in Table 6.1 are the same as those previously describedregarding Table 1.1.

TABLE 14.1 Welding Pull Rate Zone Time Solv. Ratio Temperatures (° C.)(m/min) (sec) (g/g) Solvent Type Process solvent 18.0 8.5 2.0 EMImOAc:ACN application zone: 90 1:2 (Mole Ratio) process pressuretemperature zone: 80 Process solvent 18.0 8.5 3.0 BMIm OAc:ACNapplication zone: 105 1:1 (Mole Ratio) + process pressure 0.5% (by wt.)temperature zone: 105 Cellulose Additive Process solvent 30 135 >7 (tothe LiOH:Urea application zone/process yarn 8:15 Wt % in pressuretemperature saturation Sol'n zone: −14 limit)

Referring now to FIG. 15B, which provides XRD data plots for the threewelded yarn substrates produced using the process parameters shown inTable 14.1, plot A corresponds to the first row of Table 14.1, plot Bcorresponds to the second row thereof, and plot C corresponds to thelast row of Table 14.1. In contrasting and comparing FIGS. 15A & 15B, itis apparent that the welded yarn substrates produced via the weldingprocesses and apparatuses of FIGS. 9A and 10A utilizing the processingparameters from Table 14.1, respectively, retain native cellulose Istructure of cotton while the welded yarn substrates are controllablymodified to exhibit enhanced properties and/or attributes. Thepreservation of native cellulose I structure may be achieved utilizingvarious process solvent systems and various apparatuses as previouslydiscussed in detail above.

Although the welding processes described and disclosed herein may beconfigured to utilize a substrate comprised of a natural fiber, thescope of the present disclosure, any discrete process step and/orparameters therefor, and/or any apparatus for use therewith is not solimited so and extends to any beneficial and/or advantageous use thereofwithout limitation unless so indicated in the following claims.

The materials used to construct the apparatuses and/or componentsthereof for a specific process will vary depending on the specificapplication thereof, but it is contemplated that polymers, syntheticmaterials, metals, metal alloys, natural materials, and/or combinationsthereof may be especially useful in some applications. Accordingly, theabove-referenced elements may be constructed of any material known tothose skilled in the art or later developed, which material isappropriate for the specific application of the present disclosurewithout departing from the spirit and scope of the present disclosureunless so indicated in the following claims.

Having described preferred aspects of the various processes andapparatuses, other features of the present disclosure will undoubtedlyoccur to those versed in the art, as will numerous modifications andalterations in the embodiments and/or aspects as illustrated herein, allof which may be achieved without departing from the spirit and scope ofthe present disclosure. Accordingly, the methods and embodimentspictured and described herein are for illustrative purposes only, andthe scope of the present disclosure extends to all processes,apparatuses, and/or structures for providing the various benefits and/orfeatures of the present disclosure unless so indicated in the followingclaims.

While the welding process, process steps, components thereof,apparatuses therefor, and welded substrates according to the presentdisclosure have been described in connection with preferred aspects andspecific examples, it is not intended that the scope be limited to theparticular embodiments and/or aspects set forth, as the embodimentsand/or aspects herein are intended in all respects to be illustrativerather than restrictive. Accordingly, the processes and embodimentspictured and described herein are no way limiting to the scope of thepresent disclosure unless so stated in the following claims.

Although several figures are drawn to accurate scale, any dimensionsprovided herein are for illustrative purposes only and in no way limitthe scope of the present disclosure unless so indicated in the followingclaims. It should be noted that the welding processes, apparatusesand/or equipment therefor, and/or welded substrates produced thereby arenot limited to the specific embodiments pictured and described herein,but rather the scope of the inventive features according to the presentdisclosure is defined by the claims herein. Modifications andalterations from the described embodiments will occur to those skilledin the art without departure from the spirit and scope of the presentdisclosure.

Any of the various features, components, functionalities, advantages,aspects, configurations, process steps, process parameters, etc. of awelding process, a process step, a substrate, and/or a welded substrate,may be used alone or in combination with one another depending on thecompatibility of the features, components, functionalities, advantages,aspects, configurations, process steps, process parameters, etc.Accordingly, a nearly infinite number of variations of the presentdisclosure exist. Modifications and/or substitutions of one feature,component, functionality, aspect, configuration, process step, processparameter, etc. for another in no way limit the scope of the presentdisclosure unless so indicated in the following claims.

It is understood that the present disclosure extends to all alternativecombinations of one or more of the individual features mentioned,evident from the text and/or drawings, and/or inherently disclosed. Allof these different combinations constitute various alternative aspectsof the present disclosure and/or components thereof. The embodimentsdescribed herein explain the best modes known for practicing theapparatuses, methods, and/or components disclosed herein and will enableothers skilled in the art to utilize the same. The claims are to beconstrued to include alternative embodiments to the extent permitted bythe prior art.

Unless otherwise expressly stated in the claims, it is in no wayintended that any process or method set forth herein be construed asrequiring that its steps be performed in a specific order. Accordingly,where a method claim does not actually recite an order to be followed byits steps or it is not otherwise specifically stated in the claims ordescriptions that the steps are to be limited to a specific order, it isno way intended that an order be inferred, in any respect. This holdsfor any possible non-express basis for interpretation, including but notlimited to: matters of logic with respect to arrangement of steps oroperational flow; plain meaning derived from grammatical organization orpunctuation; the number or type of embodiments described in thespecification.

The invention claimed is:
 1. A method for making a welded substrate, said method comprising the steps of: a. providing a substrate having at least two fibers therein; b. applying a process solvent to said substrate to create a process wetted substrate, wherein said process solvent is a mixture of a polar aprotic solvent and an ionic liquid, wherein the mixture has a molar ratio of at least 0.25 moles said polar aprotic solvent to 1.00 mole said ionic liquid, wherein an upper limit of said molar ratio is capped at a point at which said process solvent is no longer capable of swelling and mobilizing at least one polymer in said substrate such that said at least one polymer is capable of welding a first fiber of said substrate to a second fiber thereof in a specified duration of time, and wherein a mass ratio of said process solvent to said substrate is 4:1 or less; c. controlling at least a temperature and said specified duration of time for which said process solvent interacts with said process wetted substrate, wherein said specified duration of time is not greater than 30 seconds such that said at least two fibers are welded to one another; and, d. removing at least a portion of said process solvent from said process wetted substrate.
 2. The method according to claim 1 wherein said method is further defined such that said substrate moves in a non-linear fashion after said process solvent is applied thereto.
 3. The method according to claim 1 wherein said ionic liquid is further defined as comprising 3-ethyl-1-methylimidazolium acetate.
 4. The method according to claim 1 wherein said process solvent is further defined as being applied to said substrate at a temperature between 80° C. and 120° C.
 5. The method according to claim 1 wherein said step of removing at least said portion of said process solvent from said process wetted substrate is further defined as being performed via a reconstitution solvent to create a reconstituted wetted substrate.
 6. The method according to claim 5 wherein said method further comprises the step of drying said reconstituted wetted substrate after said step of removing at least said portion of said process solvent from said process wetted substrate.
 7. The method according to claim 1 wherein said step of applying said process solvent is further defined as being performed via an injector.
 8. The method according to claim 1 wherein said temperature during said step of controlling at least said temperature and said specified duration of time for which said process solvent interacts with said process wetted substrate is greater than a first temperature of said process solvent during said step of applying said process solvent.
 9. The method according to claim 1 wherein said polar aprotic solvent is further defined as including dimethylsulfoxide.
 10. The method according to claim 1 wherein said duration of time is further defined as not being greater than 15 seconds.
 11. The method according to claim 1 wherein said molar ratio is further defined as being between 0.25 moles said polar aprotic solvent to 1.00 moles said ionic liquid and 4 moles said polar aprotic solvent to 1 mole ionic liquid.
 12. The method according to claim 1 wherein said method is further defined such that said substrate moves in a linear fashion after said process solvent is applied thereto.
 13. The method according to claim 1 wherein said process solvent is further defined as being applied to said substrate at a temperature less than 120° C.
 14. A method of improving a yarn, said method comprising the steps of: a. providing a cellulosic-based yarn substrate; b. applying a process solvent to said cellulosic-based yarn substrate to make a process wetted substrate, wherein said process solvent is a mixture of a polar aprotic solvent and an ionic liquid having a molar ratio of at least 0.25 moles said polar aprotic solvent to 1.00 moles said ionic liquid, wherein an upper limit of said molar ratio is capped at a point at which said process solvent is no longer capable of swelling and mobilizing at least one polymer in said substrate such that said at least one polymer is capable of welding a first fiber of said substrate to a second fiber thereof in a specified duration of time; c. controlling at least a temperature and said specified duration of time for which said process solvent interacts with said process wetted substrate, wherein said specified duration of time is not greater than 30 seconds; and, d. removing at least a portion of said process solvent from said process wetted substrate to weld at least said first fiber of said cellulosic-based yarn substrate to said second fiber thereof.
 15. The method according to claim 14 wherein a tenacity of said welded substrate is at least 10% greater than a corresponding mechanical strength of said cellulosic-based substrate.
 16. The method according to claim 14 wherein a diameter of said welded substrate is at least 25% less than a diameter of said cellulosic-based substrate.
 17. The method according to claim 14 wherein a tenacity of said welded substrate is at least 20% greater than that of said cellulosic-based yarn substrate.
 18. The method according to claim 14 wherein a tenacity of said welded substrate is at least 30% greater than that of said cellulosic-based yarn substrate and said welded yarn substrate is further defined as having an elongation prior to breaking of at least 2.0%.
 19. The method according to claim 14 wherein said polar aprotic solvent is further defined as including dimethylsulfoxide.
 20. The method according to claim 14 wherein said process solvent is further defined as comprising 3-ethyl-1-methylimidazolium acetate.
 21. The method according to claim 14 wherein said duration of time is further defined as not being greater than 15 seconds.
 22. The method according to claim 14 wherein said molar ratio is further defined as being between 0.25 moles said polar aprotic solvent to 1.00 moles said ionic liquid and 4 moles said polar aprotic solvent to 1 mole ionic liquid.
 23. A method for making a welded substrate, said method comprising the steps of: a. providing a substrate having a plurality of fibers therein; b. applying a process solvent to said cellulosic-based yarn substrate to make a process wetted substrate, wherein said process solvent is a mixture of a polar aprotic solvent and an ionic liquid having a molar ratio of at least 0.25 moles said polar aprotic solvent to 1.00 moles said ionic liquid, wherein an upper limit of said molar ratio is capped at a point at which said process solvent is no longer capable of swelling and mobilizing at least one polymer in said cellulostic-based yarn substrate such that said at least one polymer is capable of welding a first fiber of said cellulostic-based yarn substrate to a second fiber thereof in a specified duration of time; c. controlling a degree to which said process solvent interacts with said substrate by adjusting a viscous drag of said method, wherein said viscous drag is a product of at least a viscosity of said process solvent and a mechanical force applied to said substrate or said process wetted substrate; d. controlling at least a temperature and said specific duration of time for which said process solvent interacts with said process wetted substrate, wherein said specific duration of time is not greater than 30 seconds such that at least said first and second fibers are welded to one another; and, e. removing at least a portion of said process solvent from said process wetted substrate.
 24. The method according to claim 23 wherein said step of applying said process solvent to said substrate is further defined as employing an injector.
 25. The method according to claim 23 wherein said substrate is further defined as a raw yarn substrate comprised of cotton.
 26. The method according to claim 23 wherein said polar aprotic solvent is further defined as including dimethylsulfoxide.
 27. The method according to claim 23 wherein said process solvent is further defined as comprising 3-ethyl-1-methylimidazolium acetate.
 28. The method according to claim 23 wherein said duration of time is further defined as not being greater than 15 seconds.
 29. The method according to claim 23 wherein said molar ratio is further defined as being between 0.25 moles said polar aprotic solvent to 1.00 moles said ionic liquid and 4 moles said polar aprotic solvent to 1 mole ionic liquid.
 30. The method according to claim 23 wherein said temperature during said step of controlling at least said temperature and said specified duration of time for which said process solvent interacts with said process wetted substrate is greater than a first temperature of said process solvent during said step of applying said process solvent. 